N Gauge Forum

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 1


Hello Chums

After wittering on in a post on my Poppingham thread about a locomotive being reboilered with a superheater, it occurred to me that modellers often use terms like this but might not be completely sure what is meant by them.

I wondered if it might be an idea to include a short series on our Fabulous Forum looking at steam locomotives from a 'N' gauge modeller's perspective.  The emphasis will firmly be on conventional British practice.  This means many fascinating experiments, developments and dead ends in steam locomotive engineering will be ignored.  Also, as this is a model railway thread, we'll be looking at steam locomotives from a 'N' gauge modeller's perspective.  Therefore, the analysis will tend towards the superficial.

I hope others, much more knowledgeable than me, will be kind enough to add their thoughts and views by way of discussion.

***

Rocket and Wheels

We need to start somewhere and, as I intend to limit my observations to the conventional 'Stephensonian' locomotive, what better place to start than Robert Stephenson's famous Rocket of 1829.?  You see, the principal arrangement of Rocket continued in mainstream British practice right through to Evening Star.  Or, if you prefer, Tornado.

We all know Rocket – a yellow locomotive with a separate tender.  A horizontal boiler, with a chimney at the front, mounted on wheels.  Driver and fireman together on a footplate behind the boiler.  Remove the adjective 'yellow' and the description could equally apply to Evening Star.  Even on the outside, Rocket set the norm for the steam locomotives that followed for more than 130 years.  And what is in the inside is even more important.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-071223145851.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137717)

[This picturingham shows Rocket, somewhat altered, in her final condition and her tender is missing.  Not yellow now!]


So, we start with Rocket.  Not the first steam locomotive and not even the first steam locomotive built by a Stephenson.  The investigation of pre-Rocket locomotives is a fascinating subject, more akin to the study of iron dinosaurs than iron horses.

As Rocket is fundamentally a horizontal boiler on wheels, we'll commence with wheels.

Right-o, as you know, Rocket looked like this, Oo – a pair of large diameter wheels at the front and a pair of smaller diameter wheels at the back.  Soon after Rocket, there were oO variants (Robert Stephenson & Co's Planet of 1830).  There were also OO locomotives, an arrangement that was also used on some pre-Rocket locomotives.

Then, in 1833, Robert Stephenson & Co. developed the OO into a OOo for the Leicester & Swannington Railway.  This was followed in 1834 (although construction commenced in 1833) by Patentee, for the Liverpool & Manchester Railway, which had a oOo wheel arrangement.  Again, in 1834, Robert Stephenson & Co built a OOO locomotive for the Leicester & Swannington Railway  Thus was born the six-wheeled 'Stephensonian' locomotive.  Not, of course, the first locomotives to have six wheels, but the first post-Rocket ones to do so.

I have deliberately omitted an important locomotive type here but we'll get to it eventually.

The next development came in 1837, unsurprisingly, from Robert Stephenson & Co, with locomotives of the oOO type for export to France and the USA.  The type entered service in Great Britain on the Great North of England Railway (between York and Darlington) which opened in 1841.

As you will have noticed, differentiating between several variations of four and six wheeled locomotives isn't easy.  And so it remained during the remainder of the Nineteenth Century with descriptions such as 'four wheels coupled passenger engine' in common use.  But, was that locomotive a oOO or a OOo?  Or, indeed, something else?

As time passed and larger locomotives, with more wheels, were making the problems of description even worse, an elegant solution appeared in a magazine article by Frederick M Whyte, published in the USA in 1900.  'Whyte notation' became immediately popular in the English-speaking world, with variations on the concept used in other countries.

Whyte notation counted a locomotive's wheels from the front and the types we have encountered thus far became:

Oo = 0-2-2
oO = 2-2-0
OO = 0-4-0
OOo = 0-4-2
oOo = 2-2-2
OOO = 0-6-0
ooO = 4-2-0
oOO = 2-4-0

Mr Whyte assumed it was normal practice to have little wheels at the front and rear of a locomotive and big wheels in the middle.  The absence of little wheels was indicated by the numeral 0 or naught.  Typically, in spoken English, this is frequently (and confusingly) pronounced like the letter 'O'.  Just like with '0' gauge and '00' gauge model railways.

Here is a practical example of what, when the 'LNWR 18-inch Goods' (commonly called Cauliflower) class was introduced in 1880, was known as a 'six wheels coupled* goods engine'.  And in Whyte notation a 0-6-0.  Much easier!


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-071223150611.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137718)

[No little wheels and six big wheels in the middle makes this Union Mills locomotive a 0-6-0.  Flossie and an interested passenger view proceedings.  Signalman Farmer stands at the bottom of his Lone Star signalbox's stairs.  He's not happy with the equivocal aspect of his Up Starting Signal.  Time to call out a S&T man


More later unless you tell me to stop.

* I'll cover the 'coupled' phenomonen in the next part.

My thanks to our MarvellousModerator @Bealman for his helpful comments on my idea for this series of postingtons and for his advice as to the most appropriate place on our FabulousForum for them to reside.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-pip

John

A nicely written starter.

However, it is usually suggested that Stephenson's PLANET was the first 'true' loco as the cylinders were at the front more or less under the smoke box, rather than at the rear.

Look forward to more, and additional posts.

Martyn

Please carry on John!

All the very best,

Tim

Please do carry on. 

I intend buying a black 5 to go with a rake of blue and grey mk 1s to cover the Cumbrian Mountain Express in the early 80s.  I've sussed out there's such a thing as rivetted tenders and otherwise but all the gubbins on top of the boiler and the various valve gear types are beyond my ken at the moment so would be handy to learn a bit more before the upcoming Farish release.

I guarantee I'll renumber one to suit 4767 and someone will say, "Pah!  That one never carried a sproghlejack top feed in preservation" or something.

Excellent, John. Please do continue. I'm sure that I'll learn a lot.

Excellently educational, keep it going please.

Quote from: SD35 on December 08, 2023, 07:59:40 PMI guarantee I'll renumber one to suit 4767 and someone will say, "Pah!  That one never carried a sproghlejack top feed in preservation" or something.

Well as you asked... 4767 is indeed a bad choice to renumber a Farish Black 5...  :(
It was uniquely fitted with 'Stephenson' valve gear instead of the standard 'Walschaerts' type as modelled by Farish.
(Hence it's preservation naming as "George Stephenson").
To their credit, Farish have recognised many of the main variations on Black 5s including long/short fireboxes, 2 dome positions plus domeless and combined dome & top-feed, welded and riveted tenders, but so far only Walschaerts valve gear, not Stephenson nor Caprotti which all look distinctly different.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 2


Hello Chums

Before we get to Part 2, thank you very much indeed to your kind response to Part 1 and to @Bealman for giving me the confidence to attempt to write this series.

Quote from: SD35 on December 08, 2023, 07:59:40 PMPlease do carry on. 

I intend buying a black 5 to go with a rake of blue and grey mk 1s to cover the Cumbrian Mountain Express in the early 80s.  I've sussed out there's such a thing as rivetted tenders and otherwise but all the gubbins on top of the boiler and the various valve gear types are beyond my ken at the moment so would be handy to learn a bit more before the upcoming Farish release.

I guarantee I'll renumber one to suit 4767 and someone will say, "Pah!  That one never carried a sproghlejack top feed in preservation" or something.

Thank you for this.  As @PLD helpfullty mentioned (4)4767 is a unique and, in my view, excellent engine.  There were 842 'Black Fives' and the class had many variations during its construction spanning the years 1934-1951.  I'm so glad you are interested in this particular locomotive and will make sure I refer to her as often as I can as the series progresses.  She has many interesting features, including her valve gear.
Incidentally, she was built at Crewe during the same month as the LMS 1500hp Co-Co Diesel Electric emerged from Derby works.

**

Frames

In this postington, we will consider locomotives built on a fixed set of frames.  Frames are parallel to a locomotive's wheels.  Which means the frames and the axles connecting the wheels, on each side of a locomotive, are at right angles to each other.

In British practice the method of constructing the frames improved as processes in other industries developed.  Starting with wrought iron, or wood and wrought iron sandwich frames, and ending up with steel plate, the basic concept was unchanged.  Something to hold the wheels in place and to which other parts of the locomotive could be attached.  This resulted in the normal British view that a steam locomotive's identity lies in its frames.

Commencing with Planet, the early Stephenson locomotives had sandwich frames outside of the wheels. This was a common but not universal arrangement at the time and, by 1840, a locomotive could have inside, outside or double frames.  For a time, some locomotive engineers compensated for weaknesses in the materials the frames were manufactured from by having double frames, one set inside the wheels and one set outside.  These locomotives are often mistakenly referred to as having 'outside frames', but double frames is correct. Double frames were especially popular in the 1850-1875 period, although their use steadily declined after 1860 or so.  The concept lingered until the early Twentieth Century, on the Great Western Railway. 

In 1876, what is believed to be the first locomotive with steel plate frames was built in Great Britain.  It was a 2-4-0 of FW Webb's design for the London & North Western Railway (LNWR), and was built at Crewe Works.  Steel plate inside frames became the norm for steam locomotives built for service in Britain.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-081223094828.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137733)

[Probably the most famous of Mr Webb's 2-4-0 locomotives for the LNWR, Hardwicke of !892.  A later development of the pioneering 1876 locomotive but, fundamentally, similar.  By this time the use of inside steel plate frames was pretty much normal practice.]


The thickness of the steel plate increased slightly over the years.  By the end of volume construction of steam locomotives in Great Britain round about 1 ¼" thickness was normal.  Incidentally, cracked frames was a problem that was unresolved at the end of steam.  If steam locomotive development had continued in Great Britain, it is a distinct possibility that an alternative to steel plate frames would have been used, at least for larger locomotives, as in other countries.

We'll gloss over, for now, the interface between the axles and the frames.  If you'll bear with me, that subject can be put in a box at present.

One final point to make about frames is how far apart they are.  This dimension was important for locomotive designers.  As the first railways were built, there was a variety of track gauges (the distance between the inside face of two parallel rails) in use.  One example is the 5 foot gauge of the Eastern Counties Railway, the first section of which opened in 1839.

There were two main gauges in use in Great Britain, George Stephenson's 'Standard Gauge' of 4' 8 ½" and Isambard Kingdom Brunel's 7' ¼" 'Broad gauge, used by the Great Western Railway and associated companies.  Places where there was a 'break of gauge', most notably Gloucester, became chaotic with passengers and goods having to transfer between standard and broad gauge trains.  The Government became concerned about this and the Board of Trade appointed a Board of Inquiry to look into the matter.  Its report in 1845 resulted in the effective ban on the broad gauge extending northwards.  This was the beginning of the end for the broad gauge and just under fifty years later, it was no more, with all the lines which used it having been converted to standard gauge.

Incidentally, the Eastern Counties Railway had converted to standard gauge in the autumn of 1844.

Although the broad gauge lingered on for almost half-a-century, there wasn't a great deal of locomotive development for it and we shall concentrate on standard gauge from now on.

For locomotive engineers, to provide all the necessary clearances and to allow for the thickness of the frame plates, standard gauge meant that the distance between the insides of the frames of a steam locomotive was about four feet.  This will become jolly important in later postingtons.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-bye

John

Do please carry on with this John, I am finding many answers to the many things I didn't know I didn't know! :D
Very well done!
Cheers :beers:

Quote from: PLD on December 08, 2023, 11:52:59 PM

Quote from: SD35 on December 08, 2023, 07:59:40 PMI guarantee I'll renumber one to suit 4767 and someone will say, "Pah!  That one never carried a sproghlejack top feed in preservation" or something.

Well as you asked... 4767 is indeed a bad choice to renumber a Farish Black 5...  :(
It was uniquely fitted with 'Stephenson' valve gear instead of the standard 'Walschaerts' type as modelled by Farish.
(Hence it's preservation naming as "George Stephenson").
To their credit, Farish have recognised many of the main variations on Black 5s including long/short fireboxes, 2 dome positions plus domeless and combined dome & top-feed, welded and riveted tenders, but so far only Walschaerts valve gear, not Stephenson nor Caprotti which all look distinctly different.

Thanks.  I guess that narrows it down to 5305 or 5407 then unless I go for one of the other classes.  Plenty of options to go at:

https://settlecarlislesteam.co.uk/headboards/cumbrian-mountain-express

Quote from: PLD on December 08, 2023, 11:52:59 PM

Quote from: SD35 on December 08, 2023, 07:59:40 PMI guarantee I'll renumber one to suit 4767 and someone will say, "Pah!  That one never carried a sproghlejack top feed in preservation" or something.

Well as you asked... 4767 is indeed a bad choice to renumber a Farish Black 5...  :(
It was uniquely fitted with 'Stephenson' valve gear instead of the standard 'Walschaerts' type as modelled by Farish.
(Hence it's preservation naming as "George Stephenson").
To their credit, Farish have recognised many of the main variations on Black 5s including long/short fireboxes, 2 dome positions plus domeless and combined dome & top-feed, welded and riveted tenders, but so far only Walschaerts valve gear, not Stephenson nor Caprotti which all look distinctly different.

i wasnt aware of these variations by Farish--please tell us more.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 3


Driving and Coupled Wheels

The next thing we need to address is the fact that a locomotive is not much use unless at least one axle and its associated pair of wheels is driven or powered in some way.  We'll, hopefully, discuss later how this can be done, but, for now, let's simply assume that, in normal British practice in Queen Victoria's time, one axle would be driven and the wheels stuck on both ends of that axle could be quite big, big-ish, big, or enormous.

Here's that dodgy picturingham of Rocket again.  The powered wheels are the quite big leading wheels and the little wheels at the rear are simply to hold the back of the engine up.  Other than that, they are pretty much just along for the ride.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-081223093433.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137731)


We now need to stop for a bit and think about a railway where flanged metal wheels run on metal rails, as was pretty much the norm after Rocket.  This results in a very low rolling resistance, but also low adhesion.  The amount of the wheel in contact with the rail is very small indeed.  Much, much smaller than the often-mentioned man's hand contact area between a motor-car's rubber tyre and the road surface.  Victorian locomotive engineers thought that the contact area for a typical driven wheel was about the size of a penny – the proper 'old money' penny.

Which meant that locomotives intended to move heavy, trundling goods trains benefitted from having more driven wheels.  The way to achieve this was simple and went back to the earliest pre-Rocket locomotives.  Drive one axle and connect one or more axles to the driven axle.  This was occasionally done in the very early years by gear-type contraptions, but soon the much simpler device of coupling rods became standard.

The coupling rods were fitted to a crank on the wheels on the driven axle by means of a crankpin.  That way, two, three, four or five wheels (in Great Britain - other countries managed six!) on each side of the locomotive could be coupled together and the number of pennies in contact with the rail increased, to the benefit of adhesion.  Especially in the rain!


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-081223094802.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137732)

[This is a replica of Timothy Hackworth's Sans Pareil, which came second to Rocket at the Liverpool & Manchester Railway's Rainhill Trials in 1829.  She was a 0-4-0 of, at the time, fairly convention design.  Her defeat at Rainhill marked the beginning of the end of the era of Steam Dinosaurs.  You can see the crank, crankpin and coupling rod.  The use of coupled wheels pre-dated the Rocket era.  However,Sans Pareil had 4d's worth of driving wheel-to rail contact and Rocket had only 2d.]


Pedants might say that wheels attached to the driven axle are called driving wheels and the wheels linked to them by means of coupling rods are called coupled wheels.  But 'driving wheels' or, colloquially, 'drivers' is a common description.  Let's not argue about this - especially in the context of model railways where 'driving wheels' is pretty much the normal term employed. But please, please, don't call the coupling rods 'connecting rods' or 'con rods'.  These are a thing, but a very different thing.

Time for another couple of well-dodgy picturinghams.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-091223150039.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137767)

[A passenger locomotive having two axles coupled by means of coupling rods - 4-4-0 in Whyte notation.  4d worth of driving wheels' contact with the rails.  She also has double frames which makes it difficult to see the diameter of her driving wheels.  On the full-sized locomotive, they are 6' 8½" - big wheels!  Please ignore the front four wheels for now.  That's something for later]


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-091223150113.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137768)     

[A goods locomotive having all six wheels coupled together by coupling rods to maximise adhesion – 0-6-0 in Whyte notation. A 'tanner's' worth of driving wheels' contact with the rails.  Conventional inside frames, although some very similar locomotives had double frames.  Big-ish wheels - 5' 2" diameter.]


Closing Comments

Writing this sort of thing is dashed tricky and I am aware I have left a few things hanging in the air.  I believe these to be:-

1)  How the axles are attached to the frames;
b)  How at least one of the axles is driven, and
iii) Why the size of the driving wheels is important; including, maybe, something more on the importance of wheel-rail contact.

Please let me know if you think there are others.

Tempting as it is to address these these matters, I'm going to remain on the subject of wheels and frames for now.  They are all, of course, inter-related, but my coarse guide is trying to keep things simple.  Hopefully, you'll join me for the next postington in the series where we will move a bit later in Queen Victoria's reign and think about - oh my giddy aunt - locomotives with more than six wheels.

By the way, a little thought.  In my view, there were two 'long' fifteen year periods where steam locomotive development in Great Britain could be described reasonably as 'revolutionary': 1829-1845 and 1901-1917.  There was also evolutionary progress in other periods as we will, hopefully, see next time.

PS Rocket has quite big driving wheels of 4' 8½" diameter.  Same measurement as the track gauge.  Dashed clever chaps, those Stephensons!


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-B

John 

Fantastic reading John, can you at some point please define connecting rods/con rods.

All the very best,

Tim

Quote from: Moonglum on December 10, 2023, 09:33:07 AMFantastic reading John, can you at some point please define connecting rods/con rods.

That will come under (b) in the "things left hanging in the air" in John's post

John,

As you know I have more or less zero interest in steam engines (or at least in the case of model railways I don't) but I have enjoyed reading the first three episodes of your new threadingham.

I look forward to learning. I've already picked up a couple of gems of which I had been hitherto unware.

Alec.

Excellent thread!

I hope you come back to Rocket when you discuss its boiler. I remember a school textbook that described most steam locomotives as essentially pre-Rocket or based on the Rocket.

As you say, what went before were clunky, inefficient machines with often bizarre mechanisms. But everything after Rocket was simply an improvement on its fundamental design. Possibly over-egging the pudding a bit, but I think makes a fair point.

Would make a lovely piece for the Journal, you know.  ;)

NeMo

Quote from: Moonglum on December 10, 2023, 09:33:07 AMFantastic reading John, can you at some point please define connecting rods/con rods.

Many thanks, Tim.  I'll describe connecting rods fairly soon.  Unless I divert myself.  And will probably include a picturingham.

*

Quote from: Invicta Alec on December 10, 2023, 04:53:43 PMI look forward to learning. I've already picked up a couple of gems of which I had been hitherto unware.

Groovy!  Thank you, Alec.  I'm attempting to include a few gems and, of course, much silliness in these postingtons.  Because 'N' gauge is such fun.

*

Quote from: NeMo on December 10, 2023, 07:02:06 PMI hope you come back to Rocket when you discuss its boiler. I remember a school textbook that described most steam locomotives as essentially pre-Rocket or based on the Rocket.

Thank you, Neale.  I'll most certainly mention Rocket's boiler.  I'd be seriously remis not to.  I agree with the textbook.  To expand slightly - Rocket, Northumbrian, Planet and Patentee.  Robert Stephenson's (who nowadays does not get the recognition he deserves - like Joseph Locke) quartet that set the development of the steam locomotive on sound engineering principles.

By the way, I have another Robert Stephenson innovation, which I think is less well known, coming up.

*

Thank you very much, chums, for those kind and encouraging comments.

All the very best.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 4


Hello Chums

More than Six Wheels

During the period from 1840 to 1860, six-wheeled steam locomotives emerged as the normal types.  2-2-2 for passenger trains and 0-4-2 or 0-6-0 for goods.  However, that was also a time of experimentation, with many fascinating variations appearing, which turned out to be evolutionary dead ends.

To my mind, there were two factors which encouraged the development of the mainstream eight-wheeled locomotive.

The Bogie

The first was the patenting of the bogie by William Chapman in 1812.  This simple device, consisting of four wheels, on two parallel axles, mounted on a frame that could pivot, was being used in the Newcastle area for wagons which carried coal.  The term 'bogie' also has a colloquial usage, probably not so common nowadays, as a small-wheeled wagon or trolley.

As far as I'm aware, the first locomotives to move away from fixed frames and having a pivoted bogie was a 4-2-0,  built by Robert Stephenson & Co in 1833, for export to the USA.  Robert Stephenson is credited with the insight that a bogie could be used on locomotives, especially those to be used on lightly-laid and rough track, which was typical of early US railroads.  Its use in the USA became widespread and, in 1840-41, the Birmingham & Gloucester Railway imported 14 4-2-0 locomotives built by Norris of Philadelphia.  Another nine similar locomotives were built for the railway by British firms.

Tank Engines

No, not @Tank , the Locomotive Superintendent of our FabulousForum!  Leaving aside Novelty, which performed badly, albeit to popular acclaim, at the Rainhill trials, early locomotives had a tender behind.  Perhaps I had better rephrase that to say they towed a tender (the name derived from maritime practice) containing coal and water.

There were certain circumstances where the tender was deemed to be rather a nuisance and it was better to carry the coal and water on the locomotive itself.  This is a tank engine.  Not a 'tank', although the erroneous term 'Thomas the Tank' appears to be gaining in popularity.

Some of these were a little bit longer and heavier (carrying all that water) than 'normal' locomotives of the time and, to support the length and spread the weight, various eight-wheeled examples appeared.  Tayleur & Co. built three 4-2-2 tank engines for the Waterford & Kilkenny Railway (No, not a British railway, but instructive) in 1846.  Daniel Gooch designed a class of 4-4-0 bogie tank engines in 1849 for the Great Western Railway (broad gauge of course).

Most importantly, I think, in 1855, Robert Stephenson & Co built five 4-4-0 bogie tank engines for the North London Railway.  These were the first of what became the standard type of passenger locomotive used by that railway company.

*

Bogie Tender Locomotives

Apart from early the examples mentioned, the I believe the first important bogie tender locomotive type was Archibald Sturrock's 4-2-2 bogie express passenger locomotive of 1853 for the Great Northern Railway.  This set a trend which continued as late as 1901 with HA Ivatt's '267' class, also for the Great Northern Railway – the last 4-2-2 type built in Britain.  This type of locomotive, as with the 2-2-2 type, is often called a single-driver or a single.  Nonsense, of course, as they had two driving wheels – one on each side.  But, the terms predated Whyte notation.  I intend to say a little bit more about these later, but let's press on back to 1860.

By then the 2-2-2 was the most common type for fast passenger work, with the 4-2-2 also being used.  However, the 2-4-0, used before then mostly for slower passenger trains, began to take over from the 'singles' on the fast work.  The 2-4-0 slowly became the dominant type for express passenger trains until the 1880s, although some railway companies remained loyal to single-driver types.

Enter the 4-4-0 Bogie Passenger Tender Locomotive.

Just think of the 4-4-0 – alongside the 0-6-0 does it not, in your imagination, typify the 'normal' British locomotives of the late Victorian and Edwardian eras?

What was the first standard gauge British 4-4-0?  Not a trick question, but it was earlier than you might think.  The Stockton & Darlington Railway* had expanded from what we often think of it.  It has rather stuck in the public conscience as it was in 1825. Robert Stephenson & Co built six bogie 4-4-0 locomotives for the Stockton & Darlington Railway between 1860 and 1862.  They were intended for use on the Barnard Castle to Tebay line and, because of the potentially atrocious weather which could be encountered over Stainmore Summit, the first two had commodious American-style cabs and looked remarkably modern.  At the time, a simple weatherboard was deemed more appropriate and the next four were so fitted.

Apart from on the Great North of Scotland Railway, which received its first 4-4-0 from Robert Stephenson & Co in 1861 and ordered no more 2-4-0 locomotives thereafter, it took the 4-4-0 bogie tender engine about 15 years to fully establish itself.

Thomas Wheatley designed a couple of 4-4-0 bogie passenger locomotives for the North British Railway in 1871 and James Stirling introduced his famous '6' class for the Glasgow & South Western Railway in 1873.  SW Johnson produced an elegant 4-4-0 for the Great Eastern Railway in 1874 and followed it up with an even prettier design for the Midland Railway in 1876.  From then until well into the Edwardian era, the 4-4-0 and 0-6-0 pretty much reigned supreme.  Although, of course, there were many locomotives with different wheel arrangements in use.  The final 2-4-0 for a British railway company was built in 1903, by Beyer, Peacock & Co, for the Stratford-upon-Avon & Midland Junction Railway, No. 13 on that line.

The first national 'census' of British locomotive occurred in 1913, courtesy of the Board of Trade's Annual Railway Returns which now included this matter.  The total number of locomotives in use by railway companies was 23,664.  Of these, 7,310 were 0-6-0 tender locomotives and 3,168 were 4-4-0 tender locomotives.  Incidentally, there were 3,700 0-6-0 tank engines.  Which means that 10,478 out of 23,664 locomotives were tender locomotives of 0-6-0 and 4-4-0 wheel arrangements.  Or 44%.

By then, only 955 2-4-0 tender locomotives remained in service and their numbers were in sharp decline.

Can you guess what was the fourth most common wheel arrangement in 1913?  Answer at the end.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-111223100346.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137811)

[The most common locomotive types for main line work in 1913 - the 0-6-0 for goods or general duties and the bogie 4-4-0 for passenger trains.]


* The Stockton & Darlington Railway was merged into the North Eastern Railway (NER) on 3 July 1863. For legal reasons, it was managed separately as the 'Darlington Section' until 1876, when the former Stockton & Darlington Railway's lines became the NER's Central Division.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

Answer: The 0-6-2 tank locomotive with 1,395 examples.  Mostly, but not always, a tank engine version of the 0-6-0 goods locomotive.

Hello John,
Wow! This is quite fascinating and I am learning a lot!
Many thanks indeed and please, carry on as much as you can.
Best regards,
Harold

Dugald Drummond, locomotive superintendent of, amongst other railways, the LSWR and Caledonian, is said to have initially declined to design locos with coupled drivers as 'it was like a laddie running wi' his breeks doon..'

But later changed his mind.

Whilst I'm already aware of most of the contents of what you're writing on this thread, I'm enjoying the way it's written. Keep it up!

Martyn

People who call the show "Thomas the Tank" are one of my pet hates. Anyone around me who does is promptly put straight.  :veryangry:

That was a great installment, by the way, John.  :thumbsup:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 5


Hello Chums

Suspension

We'll continue our discussion about frames and wheels in this postington and we'll take a typical locomotive from the end of the Nineteenth Century as our example.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-111223104448.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137815)

[A North Eastern Railway 'R' class 4-4-0, later LNER 'D20'.  A first-class passenger locomotive with big coupled wheels – 6' 10" diameter.]


The frames are there to hold the locomotive together and all manner of things are attached to the frames.  The frames are made from steel plate and, rather than being simply long rectangles, are shaped as required to allow for the design of the locomotive – for example, they are less high at the front to allow room for the bogie, than they are in the middle.

The frames are joined to each other by means of frame stretcher plates or stretchers, which are vertical fabricated plates or castings at right angles to the frame plates.  These are sometimes solid, but often have a large hole in the middle, to improve access and reduce weight.  Additional strengthening bars, such as Horwich stays, might also be used to make the frames more rigid.  Incidentally, even when fully assembled as a unit, the plural 'frames' is used in Britain.

As you are probably aware, the most common model railway practice is for the axles to revolve in holes in the model locomotive's 'chassis'; sometimes the holes are fitted with fancy bearings (let's ignore sprung or compensated models!).  This is a very simple solution but, unfortunately, won't do for the real thing.  You see, apart from some early 'boneshakers', steam locomotives are equipped with suspension, consisting of springs between the axles and frames.  Which means the axles need to be able to move up and down in the frames.

Blimey – I thought this coarse guide was meant to be simple and we now have a moving axle – or, in the case of that nice shiny locomotive in the picturingham, four moving axles (and that doesn't include the tender).

Let's ignore the springing in the bogie, simply remarking it's like a smaller-scale version of that used for the coupled wheels.  Like in any vehicle with axles, the two axles for the coupled wheels need some sort of bearings to allow them to revolve easily and reliably.  The axle and bearing has a close fit, just sufficient to allow rotation of the axle, so the up-and-down movement required by the springing has to be accommodated between the bearing and the frames.

This was achieved by the bearing being in an axlebox, which looks rather like a metal cube with a big hole through it.  The axle revolves in the hole, with the bearing surfaces lined with 'white metal'* – very similar to the stuff the Union Mills 'R' 4-4-0 is made from.  A steel axle revolving in a soft white metal lining makes for a better bearing than using another hard metal surface.  Let's not get into the metallurgy, but, for so-called plain bearings, a combination of a hard and a soft metal is best.  The axlebox is divided horizontally into halves; both parts are placed around the axle and then held together with big bolts and nuts.

Now for the clever part, the frames have vertical slots called hornguides in them and, with a bit of attention to the bearing surfaces, the axleboxes can move up and down in the hornguides.  To control this movement, a spring – almost always a leaf spring derived from road coach practice, but much bigger and heavier - is attached to the frames and bears on top of the axlebox.

The white metal has a finite life and requires to be renewed from time to time.  If the lubrication fails, friction causes the bearing to heat up and the white metal can melt and run away.  This is what is known as a hot box.  The trick was (and is) to stop before the steel axle is damaged.  Designers did not always pay sufficient attention to having a large enough surface area for the bearing surfaces in the axleboxes, which meant that certain classes of steam locomotives were prone to hot boxes.  The Midland '4F' design is an example of this.  The locomotive was more powerful than its predecessors, but the axleboxes were not given an adequate bearing surface area.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-111223112052.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137816)

[The picturingham shows a '4F' 0-6-0, a class built by the Midland Railway and perpetuated by the LMS after the 1923 'Grouping'.  Powerful locomotives, they suffered from bearing troubles.  The model is a ProperlyPoole Graham Farish example and runs very nicely indeed with no trace of bearings running hot!  She is about 30 years old.]


The great advantage of this bearing system is that, due to the slots in the frames, a locomotive can be lifted off its wheels so that attention can be given to the bearing surfaces.  Replacing the white metal lining is called remetalling.

Interestingly, Union Mills models use a sort of upside-down version of this system with the axles revolving in a slotted 'keeper plate'.  This allows the axles to move to help cope with dodgy rail joints and suchlike, although they are not sprung.  It also means that a Union Mills coupled wheelset can be taken out in one piece – nifty, eh?


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-111223112119.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137817)

[A Union Mills locomotive (a GWR 'Dean Goods' 0-6-0) from below.  Undoing the two machine screws allows the 'keeper plate' to be removed...}


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-111223112145.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137818)

[... once removed and placed upside down, the 'keeper plate' gives an almost passable visualisation of the side elevation of a locomotive's frames.]


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-111223112219.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137819)

[And here is the wheelset, removed just like the real ones are, albeit they would have had their coupling rods taken off first.  Pressing a wheel onto an axle was a Main Works job, but many steam shed were equipped with lifting gear (or a wheel drop if one is being really fancy) in order to remove a wheelset to give any attention required.]

 
I think, having now made a coarse attempt to describe how a steam locomotive's axles are attached to the frames by means of sprung axleboxes, moving vertically in hornguides, I'll go and sit in a darkened room before inviting you to join me for a discussion of how we can try to arrange to make the wheels go round.  There will be an element of 'it'll never work in theory' about this.

* White metal - an alloy of tin, antimony and copper.  Sometimes a small amount of lead is included.  The ratios of the metals vary according to the intended use.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Tickety-tonk

John

John,
many thanks for another splendid article on "steam locomotives and how to make 'em" - informative, educational and entertaining as ever!

Best wishes,
Tfc49

Thank you John,

I have finally caught up with the thread having read the first instalment before departing for a alcohol fueled weekend in London.

It became rather impossible to keep following on my hand held mobile communication device with a glass of something in the other hand.

Back up to speed now, please do carry on old chap

Best Wishes
Mike H

PS is Poppy writing these interesting postinghams

Pretty good so far John, although I would like to point out that most locos from the 1920s onward have underslung axleboxes on their driving wheels - in other words, the bottom of the axle box is attached to the spring which in turn is attached to the bottom of the frames.

Regards,

Alex

Quote from: Hailstone on December 12, 2023, 07:46:26 PMPretty good so far John, although I would like to point out that most locos from the 1920s onward have underslung axleboxes on their driving wheels - in other words, the bottom of the axle box is attached to the spring which in turn is attached to the bottom of the frames.

Regards,

Alex

Hello Alex

Thank you very much indeed for this.  I was a tad concerned that the large degree of simplification I was indulging in with these posts might have been an irritation to you and others who have a much better knowledge of steam locomotives that I will ever achieve.

I have been attempting to take a broadly chronological approach and have used typical late-Victorian practice for the last couple of posts.  I am tying myself in knots at present and think I'll need to do another 'frames and wheels' post before I can get on to cylinders, valves and motion.

My plan, if it can be called a plan, is to move forward to just before outside valve gear became commonplace - say about 1910 or so.

Then, later in the series (if I don't give up!), to do several posts under the general heading of 'later developments'.  Outside valve gear, higher boiler pressures, double chimneys (and similar), roller bearings, perhaps manganese linings (but that's maybe going too far for the thread, rotary valve gear and suchlike.  I'll certainly be keen to mention underslung axleboxes then.

As for the original Bulleid 'Pacifics' - I haven't a clue.  They probably would benefit from a series on their own.  And 'Leader' (like Paget's locomotive) I'll leave to someone else!

Thanks, again for your support, Alex.  Every time I see a 'like' from you, I think I'm maybe just about achieving what I set out to do.  And, of course, posts from you for discussion are hugely welcome.

With all good wishes

John     

Really enjoying reading these John, picked up a few bits I still didn't know, keep them coming please!
Steven

I have enjoyed your trip though the development of the steam locomotive, and would like to offer a little information myself. many years ago when I was a member of the locomotive department at Didcot, a book came out which many of us found fascinating and occaisionally useful, it is "Building britains locomotives" by James W Lowe and is still available second hand via Amazon. I still sometimes refer to it.

All the best,

Alex

If the forum is still handing trophies out, this noble gentleman deserves one.  :thumbsup:

This 'coarse' guide is actually coming along nicely, John.

For anyone who wants to delve deeper, try 'Locomotives; their construction, maintenance, and operation' by A Morton Bell, in two volumes.

This goes really deep into what the title says, and is very thorough, if a long read.

The first volume is design and construction; the second volume more with maintenance, fault finding, and some theory. There are also chapters on electric and diesel locos, including the Twins.

I've no idea if it is available second hand; my copies are from 1948 and came from a former fireman, later driver, at Colchester shed.

There are other titles available, and Wikipedia has some articles on boiler design.

Martyn

Quote from: Train Waiting on December 12, 2023, 09:01:42 PMAs for the original Bulleid 'Pacifics' - I haven't a clue.  They probably would benefit from a series on their own.  And 'Leader' (like Paget's locomotive) I'll leave to someone else!   

I wouldn't worry about that - it was only a miniaturised adaptation of Walschaert's valve gear using chains and crankshafts instead of the more usual return cranks on one axle and the union links from the crossheads, all three sets being squeezed into an oil bath.
All carefully designed and assembled, of course, so as to increase the risk of wheelslip and lineside & boiler lagging fires  :smiley-laughing:

Quote from: Hailstone on December 13, 2023, 01:55:34 PM"Building britains locomotives" by James W Lowe and is still available second hand via Amazon.

Plenty of copies also available on Abebooks.

Cheers,

Chris

Hi John,

 a really excellent thread!   Have been away from the layout for a while but this is getting me right back into things!  I confess I'd never quite understood how bearings worked and the role of the white metal alloy.  I now think I get it thanks to you and understand why hot boxes occur

Cheers

 Graham 

Quote from: SD35 on December 13, 2023, 02:20:10 PMIf the forum is still handing trophies out, this noble gentleman deserves one.  :thumbsup:

:-[

Thank you.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 6


Hello Chums

I'm Apologising Again

Oops-a-daisy!  Sorry, I'm first to admit it, but it turns out I was hopelessly optimistic when I mentioned in the last postington that our discussion would move on from wheels.  I hope this threadingham reads like carelessly-written gibberish, but it's actually jolly tricky gibberish to write.  It's all my own fault for trying to deal with one thing at a time when describing something as interrelated as a steam locomotive.  I decided to start with wheels and had intended to move on, in this postington, to discuss how the wheels are powered.  But, when attempting to write the text, I ended up tying myself in knots.

Which is a 'Poppy ate my homework' excuse...


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-131223203501.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137884)


...for this postington being about, contrary to as advertised, guess; Yes –

Wheels.  Again!

We had got to around the late Victorian period in the British steam locomotive's development.  Let's say the summer of 1894.  Imagine we have gone to the Highlands for the 'Glorious Twelfth' and are staying there until the end of September.

Great Britain started steam locomotive development and led the way for some years.  Our locomotives were generally well-built and fairly efficient by the standards of the time.  Increasingly, they were built in the railways' own workshops rather than by private locomotive building firms.  After the rapid development between 1929 and 1845 progress slowed.

Meanwhile, in the USA, development accelerated.  And locomotives tended to be built by specialised firms.  Think of the 'American' locomotives seen in so many Western films – often garishly decorated 4-4-0s.  These were used for both passenger and freight trains.  North American locomotives often had to travel for enormous distances compared to their British counterparts at the time.  Which led to the locomotives there becoming much bigger, much more quickly.

The 4-4-0 was replaced on the major US and Canadian railroads by larger locomotives with wheel arrangements such as 2-6-0, 4-6-0, 2-8-0, and 2-10-0.  Also, carrying wheels at the rear appeared, allowing 4-4-2, 2-6-2, 4-6-2 and 2-8-2 types to become commonplace.

Remember the difficulty describing locomotive wheel arrangements in Great Britain prior to Whyte notation in 1900?  Well, in North America, they got round the difficulty by giving the wheel arrangements names.  Here's some examples that made their way across the Atlantic (sorry!):

Atlantic – 4-4-2
Pacific – 4-6-2
Mogul – 2-6-0
Prairie – 2-6-2
Consolidation – 2-8-0
Mikado – 2-8-2

These names were pretty much universally applied in North America.  However, some of the later and larger locomotive types had different names for the same wheel arrangement, depending on which railroad was using them.  Confusing ++!

Following 7 December, 1941, the name 'MacArthur' was encouraged to be used instead of 'Mikado', although the latter was often shortened to the rather easier to say, 'Mike'.  Incidentally, this rebranding exercise appears a much simpler way to attempt to remove the name, 'Mikado', than Edward Thomson's rebuilding of the LNER's passenger 2-8-2 locomotives as 4-6-2s.

Having diverted us with typical Poppingham silliness, let's return to Great Britain and to our Inverness-shire shooting estate.  September is rapidly nearing its end and arrangements are being made for our return journey to Poppyshire.  A few days later, as we make our way south along the main line of the Highland Railway, we are treated to an amazing sight – a steam locomotive with ten wheels.  Oh, my giddy aunt! Yes, a Mancunian called David Jones has introduced Britain's first 4-6-0 - in the USA the type was called a 'Ten-Wheeler', but this never really caught on in Britain.

Primarily intended for goods work, the class became known as the 'Jones Goods', although the Inverness engineman I have met tended to pronounce it as "Joneses Goods".  This was an especially successful class and No. 103 remains in Glasgow, the city where she was built by Sharp, Stewart & Co.  The distinguished firm that built her was no stranger to the type, having already built many for service overseas.

The North Eastern Railway was next to introduce a 4-6-0 and many other railways followed.  Interestingly, three important northern railways, the North British, the Great Northern and the Midland never had 4-6-0 locomotives.  Likewise, the South Eastern & Chatham and the London Brighton & South Coast.

Some of the 4-6-0 designs of the late Victorian and Edwardian period were good performers, but others were rather mediocre.  Simply lengthening an existing 4-4-0 design into a 4-6-0 was no guarantee of success.  Interestingly, Mr Jones' 4-6-0 was an entirely new design.  What appears to be a similar 4-4-0, his 'Loch' class, was introduced two years later, in 1896.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-131223201909.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137882)

[A typical 4-6-0 of our period.  Resplendent in the famous LNWR 'blackberrty black' livery, this locomotive is a 'Prince of Wales' class 4-6-0, No. 86 Mark Twain.  The class was introduced in 1911.]


In 1889, five years before the introduction of the 4-6-0, the first 0-8-0 locomotives appeared in Great Britain, on the Barry Railway.  These had been built by Sharp, Stewart & Co for export to Sweden, but their customer was unable to pay for them. Beginning in 1892, FW Webb had lots of 0-8-0 locomotives built for the London & North Western Railway and some other railways introduced the type.

Incidentally, the Barry Railway examples were not the first appearance of an eight-coupled locomotive in Great Britain. In 1864/66 two 0-8-0 tank locomotives were built for the Vale of Neath Railway, two for the Great Northern and one for the Llanelly Railway.  All five had been scrapped before 1880.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-131223201124.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137881)

[An interesting British 0-8-0.  One of HA Ivatt's 'K1' class of 1901  for the Great Northern.  Class nickname, 'Long Tom'.  LNER designation, 'Q1' or 'Q2']


The 4-4-2 'Atlantic' first appeared in Britain in 1898, with HA Ivatt's design for the Great Northern Railway.  This was followed by Mr Ivatt's friend and mentor, JAF (later Sir John) Aspinall's, 'Atlantic' for the Lancashire & Yorkshire Railway in 1899.

The first 2-8-0 to be built in Britain was the Great Western Railway's '2800' Class, introduced in 1903 as part of GJ Churchward's plan for standardised locomotives.  In 1904, George Whale on the London and North Western Railway commenced rebuilding some of his predecessor, Mr Webb's, 0-8-0 locomotives as 2-8-0s.

Britain's first, and for 14 years, only 4-6-2 or 'Pacific' locomotive, The Great Bear was designed by Mr Churchward for the Great Western Railway and entered service in 1908.

I think this postington has mentioned all but one of the important developments which came after the typical British 4-4-0 and 0-6-0 types during the late Victorian and Edwardian periods.  Let's end (at last!) our present discussion about wheels at the end of 1911, the year of King George V's coronation.

Before we progress to how the wheels are driven, we'll have a quick look at tank engines – there was a plentiful plethora of types of these locomotives in the pre-1911 period.

But, before I make my escape, you might have noticed my use of 'all but one' a couple of paragraphs back.  I know we tend to think of 4-6-0s, 'Atlantics', eight-coupled goods engines and, of course, The Great Bear when we discuss locomotive progress in this period.  But we have left out the 2-6-0, which is, I think, a very interesting case for study.

Would you like to suggest what was the first British 2-6-0 – railway and year of introduction? 


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

Brilliant stuff, John. Triple  :thumbsup:

I can't quickly find a list on Google, but I think that some wheel arrangement names such as Atlantic, Pacific, were derived from the owning companies' name that introduced that wheel arrangement.

On the GER, the experimental 0-10-0 tank engine designed by James Holden was always known as the Decapod.

'Mogul' was derived from the first of this type in the UK, built for the GER in 1879, with first of class named named 'Mogul'.  This class was sometimes said to have been designed as an 0-6-0 by Adams (before he moved to the LSWR), but modified to 2-6-0 by his successor Bromley before they were delivered

Martyn

Really interesting read John, but not sure why you've got 'for 'N' Gauge Modellers'in the title, it's surely for anyone in any scale  :thumbsup:



Ed

PS: Aren't 4-4-0 wheel arrangements, which you didn't list, generally referred to as 'American'

Whilst I'm sure Martyn is generally correct that wheel arrangements were named after the company that owned the first example, I don't think that can be the case for the Mastodon! This is the 4-8-0, which is quite a rare wheel arrangement. I can only think of two companies that used it. The main one was Norfolk and Western who were so keen that they soon gave up on building 2-8-0s and never had any 2-8-2s, which was the normal progression from 2-8-0s in the American industry. The other company was the London and South Western, who's G16 class was designed by Robert Urie for hump shunting at Feltham and were tank engines.
Even rarer was the 4-10-0, which is rather alarmingly called a "Gobernador" after the first of the type, which bore that name. The engine was built for the Panama Railroad. In Panama they speak Spanish, of course, and it turns out that "gobernador" rather prosaically just means "governor" in that language. The only other engine I can think of with this wheel arrangement was No. 34 of the Gorre & Daphetid RR, but that probably doesn't count.

Quote from: Ali Smith on December 14, 2023, 11:17:07 AMWhilst I'm sure Martyn is generally correct that wheel arrangements were named after the company that owned the first example, I don't think that can be the case for the Mastodon! This is the 4-8-0, which is quite a rare wheel arrangement. I can only think of two companies that used it. The main one was Norfolk and Western who were so keen that they soon gave up on building 2-8-0s and never had any 2-8-2s, which was the normal progression from 2-8-0s in the American industry. The other company was the London and South Western, who's G16 class was designed by Robert Urie for hump shunting at Feltham and were tank engines.
Even rarer was the 4-10-0, which is rather alarmingly called a "Gobernador" after the first of the type, which bore that name. The engine was built for the Panama Railroad. In Panama they speak Spanish, of course, and it turns out that "gobernador" rather prosaically just means "governor" in that language. The only other engine I can think of with this wheel arrangement was No. 34 of the Gorre & Daphetid RR, but that probably doesn't count.

Correct.

I will modify my original post as it only applies to a few classes, I was thinking of Atlantic, Pacific, and Texas, and a couple of others

The list I've quoted in my previous post implies that there were more.

Martyn

Would the first British 2-6-0 have been a Midland Railway loco, imported from the USA ?

@joe cassidy

Quote from: joe cassidy on December 14, 2023, 11:25:26 AMWould the first British 2-6-0 have been a Midland Railway loco, imported from the USA ?

See post #36, the Midland version was not introduced until 1899.

Martyn

 :offtopicsign: This topic has suddenly gone wide, I'm scrolling to the right.

Is there a extra long line above?

Ed

@Newportnobby @Tank

Me too.........

Martyn

I noticed that earlier and had to reduce the size to 80% but that made the text small, of course.
From what I can see it's @chrism reply #30 that didn't wrap

My guess is it is the link in post #39 causing the problem

Quote from: Nbodger on December 14, 2023, 12:39:34 PMMy guess is it is the link in post #39 causing the problem

I though that, but it's back to normal now  :confused1:

It seemed to be only that page.

I've now removed the link, and it seems OK again.......sorry!

The Wikipedia entry is more or less the same.

https://en.wikipedia.org/wiki/Whyte_notation

Other sites have the names as well, but the first one I quoted was handy as it showed the wheels as well.

Interestingly, this history of the Mogul says the first UK example was a tank for the Garstang and Knott end railway circa 1870. This is the first time I've heard of this, the GER example is usually quoted as being first. Perhaps the GER was just the first tender engine in the UK of this type.

https://locomotive.fandom.com/wiki/2-6-0


Martyn

 :thumbsup:  :thumbsup:  :thumbsup:

Back to John's Coarse Guide

I may be a modern image modeller, but am really enjoying this fascinating thread. Thanks so much for going to all the effort John.

cheers

John, My thanks to you for taking the time and making a super effort with this series, I am enjoying reading it very much. As with many things like this, I am always prompted to delve into things I have read further to find out more!
Cheers :beers:

Quote from: Newportnobby on December 14, 2023, 12:32:54 PMI noticed that earlier and had to reduce the size to 80% but that made the text small, of course.
From what I can see it's @chrism reply #30 that didn't wrap

There was nothing in that post that wouldn't have wrapped - no long URLs or wide pics - and it looks properly wrapped to me.

A fascinating guide, its interesting now that I live on this side of the Atlantic, that while I used to think of Pacific's being the biggest thing out there, I now consider them as small secondary line locomotives! We didn't really have any of the huge articulated locos here in Canada, but we did have CPRs big 2-10-4 Selkirks and CN's main power at the end of steam were 4-8-4 Northerns.  There we still plenty of smaller types of course, but the distances involved also really dictated that locomotives got bigger and bigger.  What I was ignorant of when I first moved here, was realizing that is wasn't all long slow freight trains on rubbish trackwork. Much of the roadbed was exceptional and passenger speeds we often very high (the Canadian steam speed record was 112mph albeit with a smaller CPR 4-4-4)

Hope this isn't a hijack, just thought there are interesting comparisons to make

Graham

Quote from: chrism on December 15, 2023, 01:35:42 PM

Quote from: Newportnobby on December 14, 2023, 12:32:54 PMI noticed that earlier and had to reduce the size to 80% but that made the text small, of course.
From what I can see it's @chrism reply #30 that didn't wrap

There was nothing in that post that wouldn't have wrapped - no long URLs or wide pics - and it looks properly wrapped to me.

Apologies. It was someone else but it's been corrected by the removal of a long link so all is well.

Quote from: martyn on December 14, 2023, 10:48:43 AMOn the GER, the experimental 0-10-0 tank engine designed by James Holden was always known as the Decapod.

Martyn

Apologies for yet another one of my thread drifts but Martyn's note reminded me of one of my favorite picture postcards - the Holden Decapod ("The Most Powerful Engine in the World").

Ian

Hello Chums


The next postington in this never-ending series is delayed due to foreseen circumstances (going to the theatre, visiting a chum in hospital and that sort of stuff).

I'd like to thank you for all your fascinating, kind and helpful contributions - I returned home both yesterday and today to a queue of 'Alerts' which was just about as long as the queue at the motor omnibus stop after the theatre.

Thank you for your ideas about the first British 2-6-0, one of which has resulted in a frantic session in my library.  It even caused me to look at the internet, which is something I avoid when writing these postingtons.

Your excellent discussion points will inform some later posts.  I'll do my best to mention your post at the apposite time.  Thank you so much - all your comments are greatly appreciated.

Thanks again and all good wishes.

Toodle-oo

John

Morning John

What an absolutely fascinating and well written feature I absolutely love it. Just wanted to say thank you and keep up the good work   :thumbsup:

 :offtopicsign:  :offtopicsign:

Quote from: icairns on December 15, 2023, 04:10:53 PM

Quote from: martyn on December 14, 2023, 10:48:43 AMOn the GER, the experimental 0-10-0 tank engine designed by James Holden was always known as the Decapod.

Martyn

Apologies for yet another one of my thread drifts but Martyn's note reminded me of one of my favorite picture postcards - the Holden Decapod ("The Most Powerful Engine in the World").

Ian

(https://www.ngaugeforum.co.uk/SMFN/gallery/137/3276-151223160750.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137898)

All the more amazing as the GER suburban services at the time were worked by J69s with a few 2-42T and G4 0-4-4s.

The K77/LNER  N7s were still twelve years away, or so, and then only two of them.

Martyn

Quote from: martyn on December 16, 2023, 01:15:38 PMAll the more amazing as the GER suburban services at the time were worked by J69s.
The K77/LNER  N7s were still twelve years away, or so, and then only two of them.

According to the Wikipedia article about it, the Decapod was only built for political purposes in order to block the passage through Parliament of a new rival scheme for an electric railway by demonstrating that steam could accelerate passenger trains at a rate comparable to electric traction.

It achieved that purpose but was otherwise impractical for regular use, or for more to be built, since the short wheelbase and high weight would have required many bridges to be rebuilt or strengthened. Accordingly, after only 4 years, it was rebuilt as an 0-8-0 tender loco assigned to coal train workings in the March district, but proved no more capable than the G58s. It was scrapped in 1913 as nonstandard after a short working life.

:offtopicsign:  :offtopicsign:

Quote from: chrism on December 16, 2023, 01:58:35 PM

Quote from: martyn on December 16, 2023, 01:15:38 PMAll the more amazing as the GER suburban services at the time were worked by J69s.
The K77/LNER  N7s were still twelve years away, or so, and then only two of them.

According to the Wikipedia article about it, the Decapod was only built for political purposes in order to block the passage through Parliament of a new rival scheme for an electric railway by demonstrating that steam could accelerate passenger trains at a rate comparable to electric traction.

It achieved that purpose but was otherwise impractical for regular use, or for more to be built, since the short wheelbase and high weight would have required many bridges to be rebuilt or strengthened. Accordingly, after only 4 years, it was rebuilt as an 0-8-0 tender loco assigned to coal train workings in the March district, but proved no more capable than the G58s. It was scrapped in 1913 as nonstandard after a short working life.

Agreed, I was trying to keep the post short, or encourage others such as yourself to dig deeper if interested. I've several GER based books which quote aspects of the design and reason for building.

Decapod in the USA was a 2-10-0, but this was only 0-10-0.

The tender actually survived and was used behind, mainly, I think, B12s.

Martyn

One last note on the Decapod 0-10-0T, but hopefully of interest to N gauge modelers.  Here is a photo of an N gauge model scratch-built by Peter Middleton (of Highfield Models fame) that appeared in the November 1997 Railway Modeller.


The other locomotive in the photo was also built by Peter Middleton and is, I believe, an NER Atlantic 4-4-2.  Both locos were built in the 1960s.

Ian

I'm loving this whole thread - thank you.
But this:

Quote from: icairns on December 15, 2023, 04:10:53 PM(https://www.ngaugeforum.co.uk/SMFN/gallery/137/3276-151223160750.jpeg)

just looks like it would be much more at home on Sodor.

Neil

Quote from: nickk on December 16, 2023, 12:07:02 PMMorning John

What an absolutely fascinating and well written feature I absolutely love it. Just wanted to say thank you and keep up the good work   :thumbsup:

Quote from: nickk on December 16, 2023, 12:07:02 PMThank you very much.

All best wishes.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 7

Hello Chums

Thank you once again for all these jolly nice things you are saying about this threadingham and for the informative postingtons that are being made.  Thank you.

Yet More About Wheels and Frames

'Moguls'

The 'Mogul', or 2-6-0 in Whyte notation, had its origins in the USA in the early 1860s.  The type became possible due to the invention and patenting, in Great Britain in May 1857, by Levi Bissell, of a single axle swivelling truck.  Placed in front of a locomotive, the Bissel truck acted in a similar fashion to a bogie, helping to distribute the weight and guide the locomotive along the track.  This second attribute was especially important in the early days in North America, where the track had been laid quickly and sometimes roughly, without a lot of preparation, and the road-bed and was often poorly constructed.

Incidentally, as @grumbeast mentioned in his helpful post, North American track and related civil engineering improved enormously (in most instances) in the second half of the Nineteenth Century, allowing for much larger and heavier locomotives than were used in Great Britain to enter service.

More generally, please remember that patent, a type of single-axle truck became known as a pony truck.

Three years later, Robert Stephenson & Co built the first Bissell truck-equipped locomotive in this country - a 2-4-2 for the Belgian Great Luxembourg Railway.  In 1864, Robert Sinclair designed a class of 2-4-2 tank engines for the Great Eastern Railway.  These were built by Neilson & Co. and were, I believe, the first locomotives built for service in Great Britain with this feature. 

However, it was in North America that the pony truck, often called a 'lead truck', really caught on.  Even by the mid-Victorian era, Britain was beginning to fall behind the USA and Continental Europe with regard to locomotive innovation.  Especially for locomotives built for home service.  Those built by private firms for export were often more advanced designs than those favoured by British railway companies.

Eventually, Great Britain's first 2-6-0 design appeared in 1878 when Neilson & Co built fifteen locomotives for the Great Eastern Railway.  The main design work is attributed to William Adams, the Great Eastern's Locomotive Superintendent from 1873 to 1878.  Mr  Adams left for the London & South Western Railway before the design was complete and the final details, incorporating some American practice, were by his successor, Massey Bromley.  This was rather fortunate for Mr Adams because the class was not a success and was especially heavy on coal.

Interestingly, Mr Bromley, who unusually for a locomotive engineer at the time had an MA from Oxford, was appointed Works Manager at the railway's Stratford Works in 1874.  It is known that he visited the USA in 1876-77 where he saw at least one large 2-6-0 being built.  I wonder how much this influenced Mr Adams to think in terms of a 2-6-0 for the Great Eastern's heaviest coal trains.

Notwithstanding whom was responsible for what, the class were especially poor performers and heavy on coal, and the locomotives had short lives.  The last example of the class in service was scrapped as early as 1887 and the Great Eastern didn't risk another 2-6-0 design for the remainder of its existence.  Latterly, it built some truly massive 0-6-0 designs, but these are beyond our pre-1912 period at present.

Here's a works photograph of the first-built from The Engineer.  I don't know if she carried the name in service.


(https://www.ngaugeforum.co.uk/SMFN/gallery/137/6222-161223202856.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=137920)


Mr Bromley resigned from the Great Eastern in 1881 to join a friend in a engineering consulting firm.  He was killed in the Penistone accident on the Manchester, Sheffield & Lincolnshire Railway on 16 July 1884, aged 38.

From 1887 to 1895, the 'Mogul' type was not used on a British Railway as far as I can establish¹.

The next 2-6-0 type for Great Britain came as a result of interesting circumstances.  As a consequence of a failed export order, Beyer, Peacock & Co, had a locomotive left on its hands which had been intended for use in South America.  It was very similar to a large number of locomotives the firm had built for New South Wales.

To, I imagine, the firm's relief, the 'Mogul' was sold to the Midland & South Western Junction Railway in 1895.  She acquired the affectionate nickname Galloping Alice due to her gait when running along that lovely line between Andover and Andoversford.  I know that railway sounds like something from my Poppingham layout thread, but I'm not making this up – honest, Guv.

It's a happy story as she was successful, and the railway had second one delivered by the builder in 1897.  I warmly recommend C Hamilton Ellis' The Engines That Passed².  Especially, in this context, Chapter 4 'The Little Mogul of the Cotswolds'.  A charming story, expertly told, as one would expect from CHE.

The next turn of events is no less strange.  At the end of the Nineteenth Century, British railways' works were busy with locomotive construction and maintenance.  The locomotive building industry was also suffering a backlog in fulfilling orders as a consequence of the engineering workers' strike of July 1897 to January1898³.

This unfortunate circumstance, coupled with an urgent demand for new locomotives, resulted in three British railways purchasing a total of seventy 'Moguls', of distinctly American aspect, only gently modified for British requirements, from Baldwin and ten from Schenectady Locomotive Works (this firm became part of ALCO in 1901) in 1899-1900.
 
Whilst meeting an urgent need for locomotives, it is fair to say that the owning companies, Great Central (20), Great Northern (20) and Midland (40 - 30 from Baldwin and the 10 Schenectady examples) were less than enthusiastic about these imports.  Withdrawals commenced in 1909 and concluded in 1915.


A Diversion

The speed of delivery of the USA 'Moguls' was indicative of the amount of competition the British private locomotive building industry was facing.  It had less support from its home railways than the US manufacturers enjoyed, as the larger (and some not so large) British railways preferred to build locomotives in their own works at this time.

The US locomotive industry was a serious competitor to British builders.  Here are some figures borrowed from the late John Thomas' fascinating book, The Springburn Story⁴.

The Baldwin company had increased annual locomotive production from 313 in 1894 to 1,533 in 1902 and was making inroads into traditional overseas markets for British-built locomotives.

Perhaps even more worryingly, in round figures, Baldwin built the 313 locomotives with 1,400 men.  At the same time, the Glasgow firm of Neilson, Reid built 200 locomotives with 2,500 men.  British productivity worries are no recent phenomenon. 


Three Great Western Designs

The next three, yes three, British 2-6-0 designs were for the Great Western Railway.  Two different types, with double frames, were designed when William Dean was Locomotive Superintendent, entering service between 1901 and 1903.

Mr Dean commenced his service with the Great Western in 1855 and remained there until he retired in June 1902.  However, it is generally accepted that Mr Dean, who was suffering from ill-health, was something of a figurehead for his last five years in office, as George Jackson Churchward (of whom more later) was promoted as Mr Dean's Chief Assistant in September 1897.

The years of the Dean/Churchward transition saw some experimental types enter service, nominally attributed to Mr Dean, but clearly incorporating Mr Churchward's ideas.

The first Great Western 'Mogul' was a 2-6-0 variation of the experimental 4-6-0, No. 2601, of 1899 which was nicknamed Kruger⁵.  The first 2-6-0, No. 2602, built in the same year, was called Mrs Kruger!  Another eight '2602' class 2-6-0s, Nos. 2603 to 3610, were built from 1900 to 1903.  The class was very short-lived, being withdrawn by the end of 1906.

The second Great Western 2-6-0 design was the 'Aberdare' class, a much more successful design, of which 72 were built between 1900 and 1906. The nine '2602' class 2-6-0s were officially 'renewed' as additional members of the 'Aberdare' class in 1906.  There was presumably rather a lot of an accountancy exercise about this 'renewing'.

The 'Aberdares' were more successful and were withdrawn over a protracted period between 1934 and 1949.

The final Great Western 2-6-0 was a typically Churchward design, with inside frames, although it was Harold Holcroft who suggested the concept of a mixed-traffic 'Mogul' to Mr Churchward.  This was the well-known '4300' class, of which 342 were built.  The class was a synthesis of Churchward standard parts.  This class was introduced in the final year of our present period - 1911.


Bar Frames

No, not that kind of bar, although, if you have read this postington thus far, a visit might be in order for medicinal purposes.  Mention of Mr Churchward's designs reminds me that I have not, thus far, introduced you to bar frames.  These were common in overseas steam locomotive practice but, apart from early designs such as those by Edward Bury, did not find favour in Great Britain.

The American-built 'Moguls', mentioned ante, had bar frames.  Mr Churchward also used them in the de Glehn-type bogie which he favoured for his bogie locomotives.

Instead of using shaped metal plates, bar frames comprise an assembly of forged rectangular-section metal bars.  How best to describe these to a railway modeller?

Perhaps the best way will be if you imagine a plate frame as the surface of a traditional, nicely old-fashioned solid-top baseboard, like I use for my 'train-setty' table-top railways, laid vertically lengthwise along its longest edge.

Now, please imagine the framework for an open-top baseboard, as used by serious modellers (perhaps someone has a photograph) laid vertically lengthwise along its longest edge.  That, spectacularly crudely put, is the difference between plate and bar frames.

***

Here are some pretentious footnotingtons:


¹ The 2-6-0 tank engine for the Garstang & Knott End Railway, helpfully mentioned by @martyn , has caused a flurry of activity and I'll deftly postpone my thoughts on this until the next postington, which, if I don't run away, will be about tank engines.

² C Hamilton Ellis, The Engines That Passed, George Allen and Unwin, London, 1968.
 
³The strike did not affect all of the British locomotive building industry.  In Glasgow, the employees of Sharp, Stewart & Co, a public company, joined the strike, whereas those of the privately-owned Neilson, Reid & Co remained at work.  Hugh Reid, who controlled the firm, refused to join the Federation of Engineering Employers.

⁴ John Thomas, The Springburn Story, David & Charles, Dawlish, 1964.

⁵ After the Boer leader.  It is fair to say that No. 2601 wasn't a pretty locomotive.  Nos. 2602/10 weren't much better.  In my opinion, of course.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-B

John

Quote from: Train Waiting on December 16, 2023, 08:44:19 PMAt the end of the Nineteenth Century, British railways' works were busy with locomotive construction and maintenance.  The locomotive building industry was also suffering a backlog in fulfilling orders as a consequence of the engineering workers' strike of July 1897 to January1898³.

This unfortunate circumstance, coupled with an urgent demand for new locomotives, resulted in three British railways purchasing a total of seventy 'Moguls', of distinctly American aspect, only gently modified for British requirements, from Baldwin and ten from Schenectady Locomotive Works (this firm became part of ALCO in 1901) in 1899-1900.
 
Whilst meeting an urgent need for locomotives, it is fair to say that the owning companies, Great Central (20), Great Northern (20) and Midland (40 - 30 from Baldwin and the 10 Schenectady examples) were less than enthusiastic about these imports.  Withdrawals commenced in 1909 and concluded in 1915.

Smaller railway companies were also affected by this supply shortage. The Barry Railway bought five 0-6-2 'coal tanks' from the USA (https://rmweb.co.uk/blogs/entry/25144-barry-railway-k-class/) (designated K Class but known as Barry Yankees) which eventually found their way into GWR service, the last being retired in 1932.

Mike

Weren't the Barry K class  0-6-2s rather than 2-6-0s?

Martyn

Quote from: martyn on December 18, 2023, 06:42:11 PMWeren't the Barry K class  0-6-2s rather than 2-6-0s?

Martyn

Whoops!

Thank you very much, chaps, for this interesting discussion.  In 1900, the Barry Railway received five 0-6-2T engines from the Cooke Locomotive & Machinery Works.  These were Nos. 117-121 of the Barry Railway.

That same year, the builder supplied another two locomotives for use in South Wales.  These were Nos 20 and 21 of the Port Talbot Railway & Docks Co and were of the 0-8-2T type.  This company was taken over by The Great Western in 1908.

There is a splendid article, complete with drawings, by the late Dennis Allenden about these locomotives called 'Paterson To Pontypridd' in the December 1977 issue of Model Railways.  I enjoyed re-reading it when preparing this postington.  Hard to believe I first read it 46 years ago, though.

Back in the 'Roy Dock Years', Dennis Allenden contributed some absolutely fascinating articles to the magazine.  This was the last article he had submitted to the magazine prior to his death, aged only 52, the previous February.

Thanks again and all best wishes.

John

Thanks all this is so interesting  :thumbsup:

Just wondering, is the welsh connection the reason 5619 an 0-6-2 designed by Mr Collett and built in Swindon, I believe, is sometimes refferred to as a taffy tank. (no offence to anyoine Welsh obviously) . Its currently looking slightly daft sporting a cow catcher, large headlight, and bell for Polar Express duties. Still the kids love it and it a great money spinner for our small local preserved railway

All very, very interesting. Many thanks to John, and everybody who has added their two-penn'orth. I already knew about the Decapod, but not that it had such a short life, and I hadn't realised the GER was quite so innovative. And I used to think I knew quite a bit about the GER too... Looking forward to more fascinating facts!

 :toot:  :toot:

Cheers,

Chris

 :offtopicsign:  :offtopicsign:

Quote from: Papyrus on December 19, 2023, 03:12:37 PMAll very, very interesting. Many thanks to John, and everybody who has added their two-penn'orth. I already knew about the Decapod, but not that it had such a short life, and I hadn't realised the GER was quite so innovative. And I used to think I knew quite a bit about the GER too... Looking forward to more fascinating facts!

 :toot:  :toot:

Cheers,

Chris

Oil firing, most intensive steam suburban service in the world (I think), busiest station (?-one of, anyway) most powerful 0-6-0 in the UK until the Bulleid Q1....

Martyn

Quote from: Papyrus on December 19, 2023, 03:12:37 PMAll very, very interesting. Many thanks to John, and everybody who has added their two-penn'orth.

Thank you very much, Chris.  In particular, thank you for mentioning the contributors to the discussion, as that is where the really interesting stuff can be found and I'm especially grateful to them.

The GER gets mentioned in my next postington.  There might even be a picturingham of a blue tank engine - no, not Thomas.

Thanks again and all best wishes.

John

Quote from: Train Waiting on December 19, 2023, 04:30:53 PMThe GER gets mentioned in my next postington.  There might even be a picturingham of a blue ... engine

Ah yes, blue engines. I know 4-4-0s were several chapters ago, but I couldn't resist taking your cue to post a picture of what I, and a few others, think is the most elegant steam loco ever built*, Holden's 'Claud Hamilton'.

(https://www.ngaugeforum.co.uk/SMFN/gallery/138/2975-191223172455.png)

Sadly, I don't think either the UM model or the BHE kit do justice to it, but that hasn't stopped me buying two UMs.

Keep up the good work,

Cheers,

Chris

* I'm prepared to accept a counter-argument in favour of Stirling's 8ft Single...

 :offtopicsign:  :offtopicsign:  :offtopicsign:

 

Quote from: Papyrus on December 19, 2023, 05:28:39 PM

Quote from: Train Waiting on December 19, 2023, 04:30:53 PMThe GER gets mentioned in my next postington.  There might even be a picturingham of a blue ... engine

Ah yes, blue engines. I know 4-4-0s were several chapters ago, but I couldn't resist taking your cue to post a picture of what I, and a few others, think is the most elegant steam loco ever built*, Holden's 'Claud Hamilton'.

(https://www.ngaugeforum.co.uk/SMFN/gallery/138/2975-191223172455.png)

Sadly, I don't think either the UM model or the BHE kit do justice to it, but that hasn't stopped me buying two UMs.

Keep up the good work,

Cheers,

Chris

* I'm prepared to accept a counter-argument in favour of Stirling's 8ft Single...

The design was good enough to win a gold medal at the 1900 Paris exhibition...

The loco illustrated is the second series built with Belpaire boiler:the originals were round top. Credited to James Holden, the design was actually done by the Stratford design staff under Frederick Russell as Holden was ill at the time.

Later rebuilt by Gresley (actually Thompson when he was in charge at Stratford).

Martyn

Quote from: nickk on December 19, 2023, 06:47:14 AMThanks all this is so interesting  :thumbsup:

Just wondering, is the welsh connection the reason 5619 an 0-6-2 designed by Mr Collett and built in Swindon, I believe, is sometimes refferred to as a taffy tank. (no offence to anyoine Welsh obviously) . Its currently looking slightly daft sporting a cow catcher, large headlight, and bell for Polar Express duties. Still the kids love it and it a great money spinner for our small local preserved railway

Thank you very much.  Yes, the '56xx' class was designed primarily for use in South Wales.  The pre-Grouping South Wales companies had come to the conclusion that the 0-6-2T was the ideal locomotive type for working in the Valleys.  After the Grouping in 1923, when these companies became part of the even greater Great Western Railway (GWR), a survey of all acquired locomotives was carried out.  There were a fair amount of South Wales 0-6-2T locomotives in poor condition - effectively they were worn out.  Many were in good condition and the GWR commenced a programme of rebuilding them with standard or modified GWR boilers.

However, the ones in poor condition were to be scrapped, which would cause a locomotive shortage.  Mr Collett arranged for the Swindon drawing office to design a new 0-6-2T, based on the Rhymney Railway 'R' class 0-6-2T.  Design and construction proceeded quickly and the first of the new class was tested in steam in December 1924.  I'm given to understand the test was not a success as, due to a design error in how the valve gear was supported, the valve spindles bent which restricted the valves' movement.

It appears an urgent re-design was carried out and new drawings were issued to provide for the necessary modifications. There is a suggestion that the dating of the drawings was such as to imply this matter had been thought about in August rather than December, 1924.  The valve motion of the class is supposed to be particularly inaccessible due to the large support bracket for the valve gear which was then provided.

Notwithstanding, the class was successful in service and 200 were built between 1924 and 1928.  Such was the urgency that 50 of these were built by Armstrong Whitworth which delivered them at five per week.

I have heard tell of another, rather less than complimentary, name for this type of engine and wonder if @Hailstone might care to repeat it on our FabulousForum.

   
Thanks again and all best wishes

John

So interesting thank you so much, John. 6519 is our star loco at Telford Steam Railway and until recently was out on loan until she was returned for 10 year check and boiler test which she passed with flying colours  :thumbsup:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 8


Hello Chums

Tank Locomotives

If you recall, towards the end of the Nineteenth Century in Great Britain, two types of tender locomotive had become so commonplace that they could almost be described as British standard types – the 4-4-0 for passenger work and the 0-6-0 for goods and general duties.  The 2-4-0 was fast becoming outdated and the 0-4-2, although popular on the Great Northern and Glasgow & South Western for mixed traffic duties, was not that common, althought the London & South Western had some attractive examples.  Mr Stroudley's 0-4-2 passenger locomotives (he didn't like bogies) on the London Brighton & South Coast Railway were being superseded on top passenger work by Robert Billinton's 4-4-0 designs.  As for 'single driver' types, it appeared they had had their day, but something fascinating was about to happen.  That's maybe a subject for a later postington, though.

However, when it came to tank locomotives, no such apparent consensus appeared and locomotive designers seemed to delight in building locomotives with as many wheel arrangements as possible.  There could be any even number of wheels between four and 12, in a glorious diversity of arrangements.  There wasn't even a consensus between passenger and goods type – for instance, 0-6-2 or 0-6-4 tank engines were built for either type of duty, depending on the railway concerned.

Before we consider some of these wheel arrangements, let's pause to establish what a tank locomotive is.  Put simply, unlike a locomotive towing a tender, the coal and water required for its duties are carried on the locomotive and no tender is required.

The main advantages are the locomotive is shorter, saving platform space, particularly useful at terminus stations, and, in theory, it can run as happily in reverse as in forward gear.  In practice, enginemen often turned a tank locomotive to run chimney first if there was sufficient time and a convenient opportunity to do so presented itself.

The disadvantages were a shorter range before requiring to take water (and, less importantly, coal) than a tender locomotive.  All the coal and water carried on the locomotive increased its weight and water sloshing about in tanks that were higher up on the locomotive could make it unsteady at speed.

There were four main varieties of tank locomotive, having side, saddle, pannier and well tanks respectively.  Whyte notation uses a suffix to designate these types, as the following picturinghams will, hopefully, show:-


(https://www.ngaugeforum.co.uk/SMFN/gallery/138/6222-201223090146.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=138022)

Side tank - 0-6-0T

(https://www.ngaugeforum.co.uk/SMFN/gallery/138/6222-191223212312.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=138017)

Saddle tank - 0-6-0ST

(https://www.ngaugeforum.co.uk/SMFN/gallery/138/6222-191223212339.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=138018)

Pannier tank - 0-6-0PT

(https://www.ngaugeforum.co.uk/SMFN/gallery/138/6222-191223212408.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=138019)

Well tank - 0-4-0WT


At the time of the Board of Trade's locomotive 'census' in 1913, tank engines accounted for 40% of the railways' locomotive stock, with the most common types in service being:

0-6-0T = 3,700
0-6-2T = 1,395
0-4-4T = 1,233
2-4-2T = 1,004
4-4-2T =    455

These types were not in any way equally distributed amongst the railway companies.  The proportion of tank engines in railways' locomotive stock varied widely.  Some of the smaller railways, including the South Wales companies and the London, Tilbury & Southend used tank engines almost exclusively.

Amongst the larger companies, as reported in 1913, the London, Brighton & South Coast Railway's proportion of tank engines was 73%.  The Great Western came in at 55% - a third of its total locomotive stock consisted of 0-6-0 tank engines, mostly saddle tanks at that time.

As for the Glasgow & South Western, with its heavy short distance passenger services from St Enoch to Ayrshire and Renfrewshire – 7%.

The Lancashire & Yorkshire took a different approach and most of its short-distance services (and some not so short) were worked by its legions of 2-4-2T locomotives.  It put 300 2-4-2T engines into service from 1889 to 1911.  Incidentally, the Lancashire & Yorkshire built 20 2-6-2T locomotives, essentially an enlarged 2-4-2T, in 1904, but declined to build any more as the smaller locomotives were superior.  In the period we are discussing, this was not an unusual phenomenon.

The London & South Western also liked tank engines and 105 of Dugald Drummond's 'M7' 0-4-4 class were built between 1897 and 1911.

The 4-4-2T was a popular passenger locomotive on many railways.  It was sometimes a tank engine version of an existing 4-4-0 type.

Particularly in South Wales, the 0-6-2T was often a tank engine equivalent of a 0-6-0 goods engine.  Other railways built larger-wheeled examples for passenger work, although the Great Western favoured the 2-6-2T.

More unusual were 4-4-0T, 4-4-4T, 2-6-0T, 4-6-0T and 0-6-4T types.  4-6-2T classes started appearing in 1910 on the London Brighton & South Coast, London & North Western and Great Central railways.  Although we think of this type as a passenger engine, the North Eastern built 20 powerful examples of the type for goods work in 1910/11.  Right at the end of our period, in 1911, the first 4-6-4T class was introduced on the London, Tilbury & Southend.

Eight-coupled tank engines were an interesting lot.  Apart from the first 11 0-8-2T engines introduced on the Great Northern for suburban passenger work, eight-coupled tank engines tended to be used for specialised goods and shunting work.  For more general goods work, the Caledonian had six 0-8-0T locomotives.  The Great Northern decided its 11 0-8-2Ts would be better employed on goods traffic and transferred the lococotives to Yorkshire and Nottinghamshire, where they joined another 30 examples of the type which had been built for goods work.  By far the biggest user of the eight-coupled tank locomotive for general goods traffic was the Great Western which, from 1910 to 1923, built 215 2-8-0T engines of the '4201' class.

For specialised heavy shunting and banking duties, several types appeared.  The Port Talbot Railway and Docks Company obtained two American-built 0-8-2T locomotives in 1900.  More details of these are in the earlier discussion.  Home-built examples included the  Lancashire & Yorkshire's  five 0-8-2T engines in 1908 and the London & North Western followed in 1911 with what eventually totalled 30 0-8-2s.

The Great Central and the North Eastern both introduced large eight-coupled tank engines in 1907. Reflecting the diversity of opinion between locomotive engineers, the Great Central's was a 0-8-4T and the North Eastern's was a 4-8-0T.

As we saw in the discussion earlier, there was even a single ten-coupled tank engine, an 0-10-0WT, the Great Eastern's No. 20, Decapod.  Designed to show that steam-hauled suburban services could perform as well as a proposed electrically-worked railway into Essex, she performed well in a series of tests held between January and June 1903.  She achieved a gravity-assisted maximum speed of 55mph down Brentford Bank.  The GER enginemen must have been brave individuals.  Interest in the electric railway waned and she never ran again as a tank engine.  She was rebuilt as a 0-8-0 tender locomotive in 1906.  Not surprisingly, this lasted only until 1913.  The GER was correct to protect its suburban services – it carried 220,000 suburban passengers a day into and out of Liverpool Street.  However, the service continued to be worked exclusively by 0-6-0T locomotives until the first 0-6-2T engines began to appear in 1915.

Incidentally, Decapod was Great Britain's first ten-coupled locomotive.  Can you suggest what the second one was?

I suppose I ought to mention there was also a variety of little 0-4-0 tank engines, some with side tanks and some with saddle tanks, that were used for dock shunting and suchlike.

And, finally, the North Eastern Railway's gorgeous curiosity, Aerolite.  She was built in 1869, as a 2-2-2WT, to work the Engineer's saloon.  Side tanks were later added and she was completely rebuilt, in 1892, as a 4-2-2T.  Ten years later, she was rebuilt again, this time as a 2-2-4T.  The LNER made her class 'X1'.  She was withdrawn in 1933 and preserved - the LNER was good at that.  Surprisingly, there was also an 'X2' and two locomotives in class 'X3'.  Like Aerolite, these three 2-2-4T locomotives were of North Eastern origin for use on Officers' Saloons.

***

Time for another apology.

Sorry, I think this postington has gone on far too long.  But there are two matters I still wish to address with regard to tank engines before we move on to how we can make a locomotive's wheels go round.  So, one more post about frames and wheels to come.  Sorry!


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerio

John

Quote from: Train Waiting on December 20, 2023, 09:56:02 AMIncidentally, Decapod was Great Britain's first ten-coupled locomotive.  Can you suggest what the second one was?

I believe it was the Midland Railway's 0-10-0 built in 1919 for banking trains on the Lickey incline, nicknamed "Big Bertha" or sometimes "Big Emma"

Ian

Quote from: Train Waiting on December 19, 2023, 07:39:41 PM

Quote from: nickk on December 19, 2023, 06:47:14 AMThanks all this is so interesting  :thumbsup:

Just wondering, is the welsh connection the reason 5619 an 0-6-2 designed by Mr Collett and built in Swindon, I believe, is sometimes refferred to as a taffy tank. (no offence to anyoine Welsh obviously) . Its currently looking slightly daft sporting a cow catcher, large headlight, and bell for Polar Express duties. Still the kids love it and it a great money spinner for our small local preserved railway

Thank you very much.  Yes, the '56xx' class was designed primarily for use in South Wales.  The pre-Grouping South Wales companies had come to the conclusion that the 0-6-2T was the ideal locomotive type for working in the Valleys.  After the Grouping in 1923, when these companies became part of the even greater Great Western Railway (GWR), a survey of all acquired locomotives was carried out.  There were a fair amount of South Wales 0-6-2T locomotives in poor condition - effectively they were worn out.  Many were in good condition and the GWR commenced a programme of rebuilding them with standard or modified GWR boilers.

However, the ones in poor condition were to be scrapped, which would cause a locomotive shortage.  Mr Collett arranged for the Swindon drawing office to design a new 0-6-2T, based on the Rhymney Railway 'R' class 0-6-2T.  Design and construction proceeded quickly and the first of the new class was tested in steam in December 1924.  I'm given to understand the test was not a success as, due to a design error in how the valve gear was supported, the valve spindles bent which restricted the valves' movement.

It appears an urgent re-design was carried out and new drawings were issued to provide for the necessary modifications. There is a suggestion that the dating of the drawings was such as to imply this matter had been thought about in August rather than December, 1924.  The valve motion of the class is supposed to be particularly inaccessible due to the large support bracket for the valve gear which was then provided.

Notwithstanding, the class was successful in service and 200 were built between 1924 and 1928.  Such was the urgency that 50 of these were built by Armstrong Whitworth which delivered them at five per week.

I have heard tell of another, rather less than complimentary, name for this type of engine and wonder if @Hailstone might care to repeat it on our FabulousForum.

   
Thanks again and all best wishes

John

6697 was known as the Welsh pig at Didcot and was the first steam loco that I drove 46 years ago!

Regards,

Alex

Thanks for another entertaining chapter, John.

One tiny and unimportant correction:  what became the LNER J69s ran the 'Jazz' service from the west side of Liverpool Street to Chingford and Enfield on the Cambridge line. The east side suburban on the Colchester line was a mixture of 'Gobbler' 2-4-2, and 0-4-4 tanks until the mid 30s. The N7s were not around in sufficient numbers until then.

Looking forward to the next installment. Sorry for hijacking the thread so many times, but there are so many branches on the main line of this thread!


Martyn

Quote from: icairns on December 20, 2023, 02:26:03 PM

Quote from: Train Waiting on December 20, 2023, 09:56:02 AMIncidentally, Decapod was Great Britain's first ten-coupled locomotive.  Can you suggest what the second one was?

I believe it was the Midland Railway's 0-10-0 built in 1919 for banking trains on the Lickey incline, nicknamed "Big Bertha" or sometimes "Big Emma"

Ian

That's what crossed my mind. Big Bertha (43,313 lbf) was more powerful than Decapod (38,788 lbf) but the former was a tender loco v the latter being a tank loco. At the time of its build Decapod could quite legitimately claim to be the most powerful steam loco in the world

Quote from: Papyrus on December 19, 2023, 05:28:39 PM

Quote from: Train Waiting on December 19, 2023, 04:30:53 PMThe GER gets mentioned in my next postington.  There might even be a picturingham of a blue ... engine

Ah yes, blue engines. I know 4-4-0s were several chapters ago, but I couldn't resist taking your cue to post a picture of what I, and a few others, think is the most elegant steam loco ever built*, Holden's 'Claud Hamilton'.

(https://www.ngaugeforum.co.uk/SMFN/gallery/138/2975-191223172455.png)

Sadly, I don't think either the UM model or the BHE kit do justice to it, but that hasn't stopped me buying two UMs.

Keep up the good work,

Cheers,

Chris

* I'm prepared to accept a counter-argument in favour of Stirling's 8ft Single...

An entertaining little clip from YouTube about Clauds : 

https://www.youtube.com/watch?app=desktop&v=9IukNd6u3gQ

Hadn't realised there was a new build project to reconstruct one, although it seems to be in its very early stages at the moment.
PW

An entertaining little clip from YouTube about Clauds : 

https://www.youtube.com/watch?app=desktop&v=9IukNd6u3gQ

Hadn't realised there was a new build project to reconstruct one, although it seems to be in its very early stages at the moment.
PW



What a lovely little film, I too like Claud's  :thumbsup:




Ed

Quote from: martyn on December 20, 2023, 02:38:11 PMOne tiny and unimportant correction:  what became the LNER J69s ran the 'Jazz' service from the west side of Liverpool Street to Chingford and Enfield on the Cambridge line. The east side suburban on the Colchester line was a mixture of 'Gobbler' 2-4-2, and 0-4-4 tanks until the mid 30s. The N7s were not around in sufficient numbers until then.

Thank you very much, Martyn.

At the risk of repeating myself, it's the discussion where the really interesting things are found.

I knew the GER had 40 0-4-4T locomotives of class 'S44', later, LNER 'G4', and I wondered what they did.  I associate the railway with 0-6-0T and 2-4-2T types.  Now I know - thank you.

Incidentally, I hope we'll mention the GER class 'L77' (LNER 'N7') in a future postington.

*

By the way - an apology.  For reasons I cannot imagine, I managed to leave out the Barry Railway's 0-8-2T locomotives, built by Sharp, Stewart & Co in 1896, from the postington on tank engines.  This was an important type, the first of its kind in Britain.

Best wishes

John

Quote from: Train Waiting on December 20, 2023, 08:31:07 PM

Quote from: martyn on December 20, 2023, 02:38:11 PMOne tiny and unimportant correction:  what became the LNER J69s ran the 'Jazz' service from the west side of Liverpool Street to Chingford and Enfield on the Cambridge line. The east side suburban on the Colchester line was a mixture of 'Gobbler' 2-4-2, and 0-4-4 tanks until the mid 30s. The N7s were not around in sufficient numbers until then.

Thank you very much, Martyn.

At the risk of repeating myself, it's the discussion where the really interesting things are found.

I knew the GER had 40 0-4-4T locomotives of class 'S44', later, LNER 'G4', and I wondered what they did.  I associate the railway with 0-6-0T and 2-4-2T types.  Now I know - thank you.

Incidentally, I hope we'll mention the GER class 'L77' (LNER 'N7') in a future postington.

*

By the way - an apology.  For reasons I cannot imagine, I managed to leave out the Barry Railway's 0-8-2T locomotives, built by Sharp, Stewart & Co in 1896, from the postington on tank engines.  This was an important type, the first of its kind in Britain.

Best wishes

John

'A coarse guide to Liverpool Street steam suburban workings in 20th century'

I need to look up the details in my RCTS History of the LNER locos, but off the top of my head:
What became the G4 0-4-4s were used on the suburban services, but were not really found suitable. When the 'Jazz' services were introduced in 1920, it was timed around the J69s, but applied only to the west side suburban. Planned alterations to make a similar service on the east side were not made, possibly due to grouping? . The G4s, despite being specifically designed for the Enfield and Chingford services were not found suitable, having poor acceleration, though they remained on some such workings, and were later downgraded to carriage shunting. The east side being run with F4, F5, and F6 2-4-2s, as well as the G4s: I can't find reference to the J69s on the east side. The bigger F3s were used on longer outer suburban such as Bishops Stortford or Chelmsford, as well as longer country branches. The F3s were an example of what you have mentioned, a tank engine version of a tender loco class, in this case the E4s.

The N7s were only available in very small numbers until grouping, when new deliveries replaced the older, smaller tanks generally, being supported at odd times with small numbers of N2s. Stratford never got their hands on the full N7 class, which apparently they desired.

Later, of course, V1s, V3s and L1s arrived, and electrification or dieselisation replaced steam, but N7s remained active until the end of steam, together with the L1s. The N2s, V1s, V3s, and L1s were used on the longer outer suburban runs, not the inner services; they replaced older locos, including the F3s, D13s, and Clauds on such workings.

There were also cross-London trains from the suburbs direct to the docks so that workers did not have to go via Liverpool St and change trains.

Sorry to have gone down yet another branch.....

Thanks again for the thread, fascinating.

Martyn

Later-Note I've updated the info on the LNER tanks.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 9


Hello Chums

Radial axles

In mid-Victorian times, the six-wheel locomotive predominated but, as we have seen, there was a desire to design tank engines with eight wheels.  This was generally supposed to lead to an overlong fixed wheelbase, especially with larger coupled wheels, which might have annoyed the Civil Engineer and some way of achieving a flexible wheelbase was deemed desirable.  The bogie had been in locomotive use since William IV's time and, as we have noted, Levi Bissell patented a single axle swivelling truck in Great Britain in May 1857.  Both the bogie and the Bissell truck, or more commonly, pony truck, were pivoted from the frames of the locomotive by one means or another.

The idea of having an axle mounted on the main frames, but with a degree of radial movement appears to have been that of a French engineer, Edmond Roy, in 1857.  His arrangement was defective and the first practical version was patented by William Bridges Adams in 1863.  Please note the 'Bridges' part of this engineer's name or we'll get confused later.

Now for the tricky part.  A radial axle doesn't simply move from side to side, whilst remaining at right-angles to the frames.  Its movement is that of an arc of a circle.  In order to achieve this, William Bridges Adams used curved sides to the axleboxes, which moved inside hornguides with a matching curve.  Attempting to decide the optimum radius for the circle, which then decided its arc, gave locomotive engineers rather a lot of fun for the next 50 years or so.

I have to admit the radial axle sounds rather Heath Robinson, but it was employed on many tank locomotives in the period under discussion.  FW Webb, of the London & North Western Railway (LNWR), designed a development of the W Bridges Adams' radial axle.  In the W Bridges Adams' radial axle, the two axleboxes were independent of each other.  The Webb design placed the axleboxes at either end of a curved steel inner casting which moved within another steel outer casting, bolted to the locomotive's frames.  Any engineers shuddering at my coarse description will recognise the use of a cannon box.  As well as on LNWR locomotives, the legions of Lancashire & Yorkshire 2-4-2T tank engines used Webb radial axles.

The original W Bridges Adams' design was still used, notably on William Adams'¹ ever-popular 4-4-2T design for the London & South Western Railway – usually called the 'Adams Radial'.  One is preserved at the Bluebell Railway where another locomotive, the London Brighton & South Coast Railway's 0-6-2T Birch Grove, also has a radial axle.


(https://www.ngaugeforum.co.uk/SMFN/gallery/138/6222-211223160602.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=138044)


The picturingham shows an Adams 'Radial' 0-4-2T.  Bogie at the front and radial axle at the rear.


¹ They weren't related but have caused plenty of opportunities for confusion.

*

Garstang & Knott End Railway/ Knott End Railway 2-6-0T

Quote from: martyn on December 14, 2023, 01:01:42 PM[...] Interestingly, this history of the Mogul says the first UK example was a tank for the Garstang and Knott end railway circa 1870. This is the first time I've heard of this, the GER example is usually quoted as being first. Perhaps the GER was just the first tender engine in the UK of this type.

https://locomotive.fandom.com/wiki/2-6-0

I'm very grateful for that, Martyn.  Thank you.  I hardly ever use the internet for research, so it was an interesting experience for me.

I didn't notice any references given in the article and looked elsewhere on the internet.  The 'Wikipedia' website has an article which is noticeably similar to the one you kindly brought to my attention.  It quotes references and the one for the 'circa 1870' 2-6-0T is Bertram Baxter, British Locomotive Catalogue 1825–1923, Moorland, 1977, p. 30.

As luck would have it, I don't have this book (I'm going to try to obtain a copy, though).

However, EL Ahrons' The British Steam Railway Locomotive 1825-1925, Locomotive Publishing Co., London, 1927, makes no mention of this locomotive.  Perhaps Mr Ahrons overlooked it, but that would not have been typical of him.  The book, published posthumously, was based on his series of articles for The Engineer, commissioned in celebration of the railway centenary in 1925. Perhaps such an important omission would have been noted in the correspondence columns of the magazine and corrected by the three editors of the book.

I also consulted John Scott-Morgan's British Independent Light Railways, David & Charles, Newton Abbot, 1980.  This fascinating book has a chapter on the Garstang & Knott End Railway/Knott End Railway.  The railway opened between Garstang and Pilling in 1870 and appears to have been worked by two successive 0-4-0ST locomotives until 1875 when a 0-6-0ST called Farmers Friend was purchased for the line.  The remaining 0-4-0ST was replaced by another 0-6-0ST called Hope in 1883.

Again, no mention of a 2-6-0T 'circa 1870'.

What are we to make of this?  Without seeing the reference, it is difficult to say. Eventually the line got to Knott End by means of an extension from Pilling, operated by the Knott End Railway, in 1908.

But, the fascinating story doesn't end there.  You see, both Messrs Ahrons and Scott-Morgan mention that the railways did have a 2-6-0T locomotive.  She was Blackpool, built by Manning Wardle & Co. in 1909.  Mr Scott-Morgan describes her as, '... a large and unusual machine for a light railway'.  The date of 1909 is of special interest, given the extension opened the previous year.  Incidentally, Manning Wardle also delivered a 0-6-0T, named Knott End, in 1908.  The locomotives and rolling stock were pooled between the companies and ran on both sections of the line.

The Garstang & Knott End and the Knott End railways were absorbed by the LMS in the 1923 Grouping and Blackpool was scrapped in 1925 as LMS No. 11303.

*

Yet another apology!

When I first thought it might be a jolly jape to attempt to write this series, I assumed it would run to four or five parts.  Clearly, I'm greatly in need of a stern editor.  I decided to start with the wheels, then move on to what makes the wheels turn and finally the boiler.  Maybe concluding with a look at recent developments - I take these as being from 1912 onwards.

My first outline drafts regarding what makes the wheels go round keep mentioning steam, so please forget what has been advertised.  We'll discuss boilers next.


'N' Gauge is Such Fun!   

Many thanks for looking and all best wishes.

Tickety-tonk

John

Please don't edit, John, I'm enjoying this thread a lot-even though I keep sending it down a branch!

The Garstang and Knott End 2-6-0T; I think the webpage entry is a bit cross threaded, as it goes on to say the first examples in the UK were the GER Moguls-which is what I've always seen elsewhere in other articles.

Martyn

Quote from: Train Waiting on December 22, 2023, 01:56:41 PMI have to admit the radial axle sounds rather Heath Robinson, but it was employed on many tank locomotives in the period under discussion.

It was also employed on many larger and later locos too. The Cartazzi Axle, a variation of the Adams Radial Axle, was used as the trailing axle on all (I think) of Gresley's pacifics as well as his P1s & P2s and as the leading trailing axle on the W1 Hush-Hush. The trailing trailing axle on the latter was a normal Bissel truck, making it, technically, a 4-6-2-2 rather than a 4-6-4 Baltic.

The principle differences were that the Adams/Webb radial axles were true radials with curved hornguides/axleboxes and a spring arrangement to restore the axle to the centre position on straight track, whereas the Cartazzi has shorter, straight (but angled) hornguides/axleboxes, since that was easier to machine, and an arrangement of horizontal wedges such that the weight of the loco provided the necessary force to centre the axle.

A Radial truck was used on all the large GW prairie tanks, the 56xx tanks and I believe the 72xx tanks

Regards,

Alex

Purely by coincidence, friends bought me a Will's cigarette picture card album for Christmas. I think one or two are missing.

However, two of the cards give the names of loco wheel formations, with answers on the back, and another is lamp codes. Two more are 'How the vacuum brake works' and 'how the Westinghouse brake works'.




(https://www.ngaugeforum.co.uk/SMFN/gallery/138/447-251223114149.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=138135)

Martyn

Nice gift, Martyn. Does it explain on the back of each card what the letters denote?

Quote from: Newportnobby on December 25, 2023, 11:46:51 AMNice gift, Martyn. Does it explain on the back of each card what the letters denote?

Yes, Mick.

Each card has an explanation on the back. There are a number of subjects; it's not dated, but wagon liveries appear to be the pre-1935 type, and illustrated locos are in Big 4 liveries.

I'll need to go through it a bit more thoroughly!

Martyn

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 10


Hello Chums

After a break to recover, I'm ready for what I thought would be the third part of this little series, but it turns out it's the tenth.  As for its subject matter, let's hear from GJ Churchward:

'The modern locomotive problem is principally a question of boiler.'¹

I suppose, with the fascinating exception of fireless locomotives, the defining characteristic of a steam locomotive is its boiler.  And, as regards time, trouble and expense, the boiler is the critical component of a steam locomotive.

A quotation from LTC Rolt serves to illustrate this point:

'... the heart of the locomotive, the boiler, had been entirely rejuvenated at a cost, as it subsequently transpired, of six hundred pounds.  Truly a magnificent contribution to the railway.²

Boilers had been around for many years, but our story starts in 1802 with Richard Trevithick's  Pen-y-Darren locomotive, generally accepted as the first steam locomotive to run on rails.  This set the overall pattern for the early 'steam dinosaur' locomotives built until 1829 and, in some instances, even later.  These early locomotive featured single flue boilers with the fire at one end and the hot gasses passing from the fire through a flue tube contained inside a horizontal boiler.

The flue was often 'U'-shaped, with the chimney at the same end of the boiler as the fire.  This is called a return flue and allowed the hot gasses to pass twice through the boiler, pretty much doubling the heating surface where the hot surface of the flue was in contact with the water in the boiler.

Return flues were not universally used, for example George Stephenson's Locomotion of 1825 for the Stockton & Darlington Railway used a single through flue of two feet diameter.

These early locomotives had high chimneys to help draw the fire.  Timothy Hackworth's Royal George locomotive of 1827, an 0-6-0, introduced an especially important feature; a blastpipe with a narrow orifice aligned within the chimney so as to use the exhaust steam from the cylinders to help draw the fire through the boiler flue.  The harder the engine worked, the stronger the blast and the more powerful the draw on the fire – a kind of magic.

Typically, these early locomotives had a boiler pressure of 50 pounds per square inch (psi).  This was a significant step forward from the near atmospheric steam pressure used by James Watt thirty or so years earlier.  Watt had declined to use higher pressure steam due to the risk of boiler explosions, given the primitive state of boiler making at the time.  Techniques had improved the intervening years which allowed higher steam pressures to be used.  Albeit, not always safely, as we shall see.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-280524181312.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142269)


The picturingham shows a replica [note the LNER-style gauge glass] of Timothy Hackworth's Sans Pareil, the original of which was built for the Rainhill locomotive trials of the Liverpool & Manchester Railway in 1829.  This is a good example of a conventional steam locomotive of the time, with its return flue boiler pressed to 50psi.  The fireman stood at this end and the driver was at the far end, an arrangement dictated by the return flue.

Perhaps this is the most convenient time to mention that locomotive boilers are almost always placed horizontally, as seen on Sans Pareil, but vertical boilers have occasionally been used.  Braithwaite & Ericsson's Novelty, also built in 1829 for the Rainhill trials, was of this type.  Vertical boilers were commonplace for other applications for many years, but we won't consider them further.

I have mentioned two of the three Railhill contenders.  The next part will consider the role of the third contender in the development of locomotive boilers. And we will see the contribution made by Messrs Neville and Booth.

¹ GJ Churchward Large Locomotive Boilers paper read to the Institution of Mechanical Engineers in 1906.

² LTC Rolt, Railway Adventure, The Country Book Club Edition, London, 1962, p144.

Mr John Alcock, Managing Director of the Hunslet Engine Company of Leeds had joined the Talyllyn Railway Preservation Society and offered to help get No. 4 Edward Thomas, a former Corris Railway engine, in service.  She was built by Kerr Stuart and Hunslet had taken over the goodwill of that company when it closed.  She returned for the 1952 season.  £600 at 1952 prices would be around £15,000 in 2024.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-pip

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 11


Hello Chums

It was at  the Rainhill Trials of the Liverpool & Manchester Railway in 1829 that the steam locomotive appeared in pretty much its definitive form with Robert Stephenson's 0-2-2 Rocket.  I said 'pretty much' because it was really his Planet 2-2-0 of 1830 which established the truly definitive form.  However, his Northumbrian 0-2-2, also of 1830, was an important intermediate type as we shall see.

Rocket was the first railway locomotive with a multitubular boiler of the type almost universally used ever since.  Instead of a single large diameter flue of either the through or return type, the boiler contained many small diameter tubes.  Rocket's firebox has been partly opened over the years and the holes for the tubes can be seen easily by an interested observer.  Even with the limitations of my coarse photography, four holes can be seen.

(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-280524220100.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142270)

This important development was no more an invention of either George or Robert Stephenson than the blastpipe, which Rocket also had.

I understand the earliest use of a multitubular boiler was made by Mathew Boulton, James Watt's business partner, in 1780.  In this boiler, for a pumping engine in Cornwall, Mr Boulton used copper tubes through which the fire passed.  Mr Boulton did not patent this development and multitubular boilers were subsequently used in other locations in Cornwall.

In 1803, Arthur Woolf, a Cornish engineer, patented a boiler where the water was in tubes with the fire outside – an early use of a water tube boiler.  There were other experimental applications round the same time and, in 1826, James Neville was awarded a patent for a boiler with vertical tubes surrounded by the water, through which the hot gasses from the fire passed on their way to the chimney.

Meanwhile, in 1828, Marc Séguin had obtained a French patent for a multitubular boiler.  However, writing in his book De l'Influence des Chemins de Fer in 1839, M. Séguin admitted that the first application of a multitubular locomotive boiler was on the Liverpool & Manchester Railway.

I think the story becomes interesting because the Rainhill Trials were, in effect, a commercial competition.  The secretary to the Liverpool & Manchester Railway Company was Henry Booth.  From a present-day perspective, one would imagine him to act as an impartial administrator for the Trials.  This does not seem to have been the case.

In fact, it appears Mr Booth collaborated with George and Robert Stephenson on Rocket's design and suggested the use of a multitubular boiler.  It is my understanding that Mr Booth claimed to be unaware of the work of Matthew Boulton or of Mr Neville and M. Séguin's patents.

As can be seen in the picturingham, Rocket had its fire in a separate firebox at the rear of the boiler.  There were four copper pipes connecting the water jacket around the firebox to the boiler to allow for circulation of water.  OVS Bulleid had a similar idea with the thermic syphons fitted to his 'Pacific' locomotive classes built for the Southern Railway about 120 years later.

Northumbrian dispensed with the external firebox in favour of an internal firebox contained within the boiler, rather than as a separate component.  Planet also used this arrangement which became standard practice for locomotive boilers and remains so to the present day.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-290524094346.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142273)


Incidentally. Rocket's working pressure was 50 psi but the boiler was tested to 150 psi which gave Robert Stephenson valuable experience in the use of stays to hold the boiler in its desired shape.

Having arrived at the modern locomotive boiler as early as 1830, developments occurred gradually over the years.  I will cover some of these, together with an outline description of a typical locomotive boiler in subsequent postingtons.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Tickety-tonk

John

Excellent! :beers:

Fascinating reading John, it is hard to believe that this was all happening 200 years ago!

All the very best,

Tim

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 12


Hello Chums

We have ascertained that the locomotive boiler reached what became its standard form with Robert Stephenson's Northumbrian of 1830.  We also found out a little about the various early experiments with boilers, including Arthur Woolf's 1803 patent for a boiler with water inside the tubes and the fire outside.  We will return to this principle later – it took about seventy years after the appearance of the 'Stephensonian' boiler before the idea of something other than hot gasses in tubes was considered seriously for locomotive boilers.

So, for this part, we'll consider locomotive boilers in the 1830-1900 period and I'll try to stick to British practice.

The picturingham shows a typical late 19th century locomotive – in this case a North Eastern Railway 'R' class 4-4-0 of 1899.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-290524120626.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142278)


One can see the boiler is horizontally-mounted on top of the frames and its diameter allows clearance for the large coupled wheels, 6' 10" in this case, outside of the boiler.  The end of the boiler nearest the cab contains the internal firebox (just like Northumbrian of 69 years earlier), the middle part is the multitubular boiler and the black-painted part at the front is the smokebox, where the hot gasses from the fire are drawn through the tubes and ejected up the chimney by the action of exhaust steam from the cylinders passing  through the blastpipe – a system we noted was devised by Timothy Hackworth in 1827.

This is what we modellers tend to think of with regard to the boiler, firebox and smokebox, but it really is just the external cladding and paint (SuperSpiffing 'Saxony' Green in this instance) that we are bothered about.  For steam locomotive people, these are the least of their worries.

I thought it might be a wizard wheeze to show you a somewhat similar boiler without its fine outer clothing.  Persons of a nervous disposition (and rivet counters!) are advised to look away now.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-290524120653.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142279)


Not quite so pretty. Smokebox at the front, complete with its opening door to provide access, multitubular boiler in the middle and the part containing the internal  firebox, called the outer firebox, at the far end.  The internal firebox quickly became known as the 'inner firebox' and we'll use that terminology from now on.

Before closing this part, let's have a quick think about how the boiler is attached to the locomotive's frames.  It's important to remember that the frames are of fixed dimensions but the boiler will expand due to heat.  This expansion must be allowed for or we'll be in lots 'N' lots of bother.

The steam has to pass from the boiler to the cylinders, which are fixed to the frames, and then back to the blastpipe in the smokebox, accurate positioning of which is critical to the performance of the engine.  Therefore, the smokebox end of the boiler is fixed to the frames and all the expansion is allowed for at the firebox end.  You can see the expansion brackets rivetted to the outer firebox sides – the outer firebox fits neatly between the frames and these brackets slide along the top of the frames.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-290524120722.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142280)


Locomotives with wide fireboxes, over the frames, use a variant of this system.  Well worth looking for the next time you examine a Bulleid 'Pacific'.

**

Please note my flimsy excuse for the more egregious oversimplifications is that these postingtons are in the context of tiny trains with low voltage electric motors and not glorious big, hot steam engines, complete with high pressure live steam [v. v. hazardous].

**

I'd like to record my sincere thanks to the wonderful people at the Lakeside & Haverthwaite Railway who regard my continuing exploration of the nether regions of their lovely steam locomotives with relaxed equanimity.  I commend this line to you, both for the trains and for the bacon rolls, coffee and scones served in Mrs Maher's excellent refreshment room.


'N' Gauge is Such Fun

Many thanks for looking and all best wishes.

Cheerie-bye

John

Thank you John for another wonderful history lesson

Awesome.:thumbsup: I have visited the railway, and the gentleman who showed me around inside was a so enthusiastic, he was almost babbling! But it was great.

Not to be missed.  :beers:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 13


Hello Chums

We have seen a side view of a locomotive's boiler, photographed in the rain at Haverthwaite.  If we nip round the SuperScenic Cumbrian coast far a while we arrive in Ravenglass and, in the Ravenglass & Eskdale Railway's fine new museum, we meet a cutie called Katie.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300524150104.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142289)


See what I mean?

Shimmying round we can see the part of her boiler that concerns the enginemen for most of the time.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300524150132.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142290)


The firehole door, through which, when opened, the fuel is shovelled onto the fire can be see.  As can these jolly important items, the gauge glasses, which show how much water there is in the boiler.  As a recent reconstruction, Katie has two of these. Please note they have 'zebra stripes' - this was an LNER idea and is pure dead brilliant as they say in a city to the west of here.  Prior to this clever wheeze, an empty gauge glass could be mistaken for a full one with potentially explosive consequences.  Literally.  When viewed through water, the stripes change direction¹, greatly reducing the likelihood of a potentially fatal misreading of the water level in the boiler.

If we move up to a bigger scale – no, we aren't going '00' – we can see the arrangement on a standard gauge locomotive.  In this case, London & North Western Railway 'Precendent' 2-4-0 No. 790 Hardwicke.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300524150203.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142291)


She has only one gauge glass – she will also have try-cocks, which later fell out of favour with British railways when two gauge glasses became the norm².  Apart, of course, from on the Great Western.

Her firedoor is bigger than the one we saw on Katie and the two prominent pipes and valve wheels on the faceplate [backhead for GWR people] are for the injectors.  Important things, injectors.  They force cold water into the boiler against the pressure of the steam.  Jolly clever, that.  All done by steam pressure and cones.  Not the seaside sort - they are made, carefully, from metal.

**

¹  Just in case Percy Pedant is about to tell me off, the stripes don't actually change direction, they just appear to do so.

² This took a while.  Here is the incomparable David L Smith writing about the new LMS '3F' 0-6-0T shunting engines which the LMS allocated to the Glasgow & South Western section from October 1924:

'They were truly terrible.  The first thing that caught the eye was the lever reverse; we had had power reverse on our engines since 1875.  There was only one gauge glass; we had had duplicate glasses since 1879.'

 
'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

I don't know where I read it, and it was a very long time ago, but I'm sure that a piece I've seen said that the injector was originally designed (by Giffard) to refill boilers on a proposed airship!

But that could be a faulty memory......

I don't know if John will cover it, but injectors replaced mechanical pumps, powered usually from an axle or from the valve motion,, which forced water into the boiler. This meant that on occasion, a loco had to be moved just to operate the pump and refill a low boiler. In a terminus this could cause problems, and again, I'm sure I've read in the long distant past that this could mean placing the loco against the buffer stops, applying copious oil to the track, and running at slow speed....

Martyn

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 13 - Supplemental


Hello Chums

I included a picturingham of Hardwicke's footplate in Part 13.  I though it impolite not to show the whole engine.  Here she is:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300524154534.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142292)


And her combined name and builder's plates - August 1873:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300524154643.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142293)

**

Quote from: martyn on May 31, 2024, 09:52:55 AMI don't know where I read it, and it was a very long time ago, but I'm sure that a piece I've seen said that the injector was originally designed (by Giffard) to refill boilers on a proposed airship!

But that could be a faulty memory......

]...]

Thank you, Martyn and that might well be the case.  M. Giffard built a steam-powered airship.  And... it flew (or so I understand)!

Certainly, the injector he invented in 1859 (others had a similar idea but Henri Giffard got it right) transformed steam on rails.  Sharp, Stewart & Co. obtained the patent rights for the United Kingdom in 1860 and the feedwater pump quickly became obsolescent, except when locomotive engineers experimented with pre-heated feed water.  Mr Stroudley used crosshead pumps to deal with hot feed water on the LB&SCR.  On the G&SWR, James Manson with 4-6-0 No. 129 and, less successfully, Peter Drummond with the fifteen 0-6-0 engines of the '279' class, used steam-driven pumps which removed any requirement for furious motion to replenish the water in the boiler. No. 129 also retained her two Gresham's injectors.

**

If you peer at the second well-dodgy picturingham, you might just notice the fine yellow line between the red and grey lining.  It was to do that line on an '0' gauge model that the late Bernard Millar resorted to the use of a tiger's whisker.


'N' Gauge is the Cat's Whiskers

Many thanks for looking and all best wishes.

Toodle-oo

John

Brilliant stuff, John - thank you so much  :thumbsup:

I seem to recall having seen 'Hardwicke' at the railway museum when that was in Clapham :hmmm:

Hi John,

 Wonderful posts as usual!  I confess that while I am riveted (pun intended) by the excellent and detailed information you share, My wife enjoys me prattling on about trains at night as it helps her get to sleep and the information you shared about boiler design really did the trick last night!

In all seriousness, she is in significant pain because of her CP and its honestly really helps distract her (although the number of times I've waxed lyrical about the wonders of steam over Shap, up the Lickey and and the magnificence of Ribblehead, you'd have thought she'd be bored of it by now!

I'd have to go through my RCTS books, but as injectors were generally designed to operate with cold feedwater from the tanks, some classes of locos which condensed steam back into the tanks, usually because of working through tunnels, had problems with the subsequent hot water feed.

To overcome this, I think that some classes used pumps in addition to injectors, and some types of injectors were later designed to be able  use hot water feed as well as cold.

And of course, hinted at by John, as well as designs by loco engineers, there were a number of 'patent' boiler feed designs which used pumps as the water was usually hot and was a form of fuel economy.

This includes such makes as ACFI (used on some but not all B12s, the first P2, and a couple of A3s amongst others on the LNER), DABEG, etc.

Martyn

Quote from: Train Waiting on June 01, 2024, 08:41:04 AMA Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 13 - Supplemental

Quote from: martyn on May 31, 2024, 09:52:55 AMI don't know where I read it, and it was a very long time ago, but I'm sure that a piece I've seen said that the injector was originally designed (by Giffard) to refill boilers on a proposed airship!

But that could be a faulty memory......

]...]

Thank you, Martyn and that might well be the case.  M. Giffard built a steam-powered airship.  And... it flew (or so I understand)!

This was on my mind this afternoon at the West Wales Railway Modellers' Show, where their O Gauge Group displayed models of several other steam powered vehicles of that era.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/2947-010624203910.jpeg) (https://www.ngaugeforum.co.uk/SMFN/gallery/142/2947-010624203910.jpeg)

I do hope you'll be able to cover some of these other 'ahead-of-their-time' developments in this excellent series John.

Mike

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 14


Hello Chums

You know how some people consider the Nineteenth Century to be a period of unbridled laissez-faire capitalism, free of government regulation?  Like so many perceptions, this is totally wrong and it is my contention that was the century during which something like the modern system of regulation evolved.  In this part we shall see that the consequences of an Act of Parliament of almost two centuries ago are still relevant today.

**

At this point, I think it would be handy for us to see inside a locomotive's firebox.  But that's a dashed tricky place for a coarse photographer, with well dodgy legs, like me, to take a picture.  But...wait a moment – I have a cunning plan.  I know a bloke in NSW who is a dab hand with a camera; I'll arrange for him to take the photograph for us.

[Brief pause for aeroplanes and suchlike... please talk amongst yourself.]

Sorry for the delay, it took longer for @Bealman , our photographer, to get from the 'Gong to York than I expected.  Maybe he was idling away the time in licensed premises, various, with pints of Broon. Here's the very nice picture:-


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300524155553.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142294)


A BIG Engine this time.  Rebuilt 'Merchant Navy' 4-6-2 35029 Ellerman Lines at the National Railway Museum in York.  Helpfully, George got busy with a 'Junior' hacksaw before taking the photograph so we can see inside the locomotive's firebox.  And, if you are interested in this sort of thing, there is a lot to see.

Too much to describe in one postington.  So, we'll start with that strange pinky-brownish-red coloured thing crossing the firebox.  Sort of brick coloured?

That's not a surprise because it's called a brick arch and one of these can be found in the firebox of almost every standard gauge locomotive for railway service.  Industrial engines don't usually have them.  The reason it's there goes back to the Liverpool and Manchester Railway Act of 1826¹.  I assume our legislators had seen or heard tell of the 'steam dinosaurs' that were clanking their way across Northumberland and County Durham shrouded in clouds of acrid smoke.  Parliament included a provision in the 1826 Act which required any steam locomotives used on the railway to 'effectively consume their own smoke'.

This requirement was included in the rules for the Rainhill Trials of 1829.

The consequence of this can be imagined and the incomparable EL Ahrons (1866-1926) describes it much better than I can:

'Although coal [as a fuel] was not prohibited, the result of the Act was that from 1829 coke for many years became the universal fuel on main line railways other than the Stockton and Darlington and one or two other lines in the Durham area.'²

Coke was much more expensive than coal and locomotive engineers spent many years attempting to work out how to burn coal cleanly in an engine's firebox.  Some of the resulting contraptions were ingenious but all were impracticable to a greater or lesser extent.  Finally, the problem was solved by Charles Markham and Matthew Kirtley on the Midland Railway.  By 1860 they had arrived at the solution we know to this day - a brick arch built across the firebox and a sloping deflector plate placed above the firehole.  This caused air entering through the firehole ('secondary air' to enginemen) to be deflected on to the surface of the fire which improves combustion.

The brick arch and deflector plate were quickly adopted and the use of coke was almost completely phased out.  Incidentally, the Ravenglass & Eskdale Railway continued to use coke until 1980.  Coke burns hot and could cause distortion of the boiler tubes, leading to leaking tubes.  One afternoon, three out of the four engines in service that day failed with leaking tubes and the railway changed to coal firing.³

What we would now call environmental protection legislation, dating back to King George IV's time, has been an important factor in steam locomotive development and continues to be so.

We'll continue looking inside the firebox in the next part.

By the way, the near contemporaneous invention of the injector and solution to the problem of coal firing represents something of a turning point.  Until 1860, most innovations regarding steam locomotives were made in the United Kingdom.  After 1860, innovations tended to be from abroad - not totally, of course, but to a large extent.  M. Giffard, whom we met earlier, with his injector is the start of a trend.  I expect we might hear soon about two famous Belgians. 


¹ Liverpool and Manchester Railway Act 1826 (7 Geo. IV. c. xlix) of 5 May 1826.

² Ahrons EL, The British Steam Locomotive from 1825 to 1925, Locomotive Publishing Company, London, 1927, p130.

³ Railway World, Vol 45, No. 531, July 1984, p370.

Special thanks to George for the picture.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

You're most welcome. An excellent education, yet again. Interesting to see Durham and Northumberland being the rebels!  ;D

From memory, I think that Beattie on the LSWR invented a fire box with two furnaces, with the idea that the second, higher up, fire would 'consume' the smoke.

But again, I could be wrong, and have no idea where I read this.

Martyn

Martyn

Hi some history
@martyn


I noticed this

https://www.brc-stockbook.co.uk/beattie.htm

https://preservedbritishsteamlocomotives.com/30585-lswr-314-lswr-0314-sr-e0314-sr-3314-br-30585/


Was it the well tank?

I was looking at something else but it caught my attention

Thanks John for your history lessons

Quote from: martyn on June 02, 2024, 07:35:38 PMFrom memory, I think that Beattie on the LSWR invented a fire box with two furnaces, with the idea that the second, higher up, fire would 'consume' the smoke.

But again, I could be wrong, and have no idea where I read this.

Martyn

Thank you, Martyn; you are absolutely correct.

Attempts to burn coal using some type of double firebox arrangement commenced, I believe, with John Dewrance's locomotive Condor for the Liverpool and Manchester Railway in 1845. 

James Cudworth on the South Eastern Railway used a similar approach from 1857 and some of his engines with this feature were in service as late as 1891.

From 1853, Joseph Beattie on the London & South Western Railway featuring some type of double firebox and a variety of other gadgets, including hollow stay bolts.  One can only wonder what the railway's boilersmiths thought of such exotica.  Mr Beattie was certainly an innovative engineer.  He became unwell and died in 1871 being succeeded by his son, William Beattie, who persevered with double fireboxes until 1877*.

Unfortunately, William Beattie was not successful and, following the many troubles associated with his 20 outside-cylinder 4-4-0 locomotives of 1876/77, resigned his appointment on the grounds of ill health.  William Adams succeeded William Beattie and mechanical orthodoxy came to the L&SWR's locomotive department.


*Beattie engines also had feedwater heaters and pumps.

With all good wishes.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 15


Hello Chums

We left Part 14 with a look inside a locomotive's firebox and a discussion about how the addition of a brick arch and a deflector plate allowed coal to replace coke as the normal fuel - at least in Great Britain.

We also established that the external firebox seen on Rocket was soon replaced by an internal, or inner, firebox contained within the boiler.  It is convenient to think of the firebox as a ... box.  A roughly cube-shaped box, normally (in British practice) made of copper and surrounded on five sides by water in the boiler.

The sixth side, the bottom of the box, is open with a grate arrangement using firebars to support the fire.  Firebars are important as they allow the all-important air to flow through the grate to permit the fire to burn.  Enginemen call this 'primary air'.  The firebars also allow ash from the burnt coal to drop through the grate into the ashpan.  Without this feature, the fire would clog with ash and the locomotive would run short of steam.  Without a grate with firebars, there would be no steam-worked 'Non-Stop' between KX and the Waverley (at least not coal-fired) and we would be deprived of this cinematic paragon of post-War British culture. "Bath buns for blonde belles" indeed.


https://www.youtube.com/watch?v=ghkqGfUy4xs


Over time, the grate arrangement became more sophisticated with rocking firebars to clear clinker and a way of moving the grate to allow the fire to be dropped into the ashpan and raked out during disposal on shed.  On older engines, the remains of fire was cleaned out ('baled out' or 'paddled out' are other terms I've heard) with a long shovel through the firehole or the firedropper removed a couple of firebars with a sort of long tongs and pushed the fire through the gap and into the ashpan*.

   
(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-140624092614.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142506)

This crop of George's helpful photograph shows the grate of a 'Merchant Navy' 4-6-2 with the
ashpan below.


And here is an example of a firebar, in this instance from an LMS '5MT' 4-6-0:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-140624095319.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142515)


Do you have a locomotive's firebar in your garden as well?


* MF Higson in London Midland Fireman, Ian Allan, London, 1972 SBN 7110 0321 1, has a fascinating discourse on fire cleaning, including the difficulties of removing firebars.  It's on page 45 et seq.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

Fascinating stuff as always, but the commentary on the film falls a long way short of "Night Mail". No wonder W. H. Auden is more famous than Paul le Saux.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 16


Hello Chums

We have seen how a typical steam locomotive, from Robert Stephenson's Northumbrian of 1830 until the present day, has an inner firebox, usually made of copper, and an outer firebox as part of the boiler shell, made of iron and, later, steel.  There is  water surrounding the inner firebox apart from at the firegrate at the bottom. We might look at some of the figures later, but a combination of temperature and pressure means that it is vital for the strength, and safety, of the boiler that the inner and outer fireboxes are firmly secured to each other.  Maintaining this condition is an essential for the safe working of a steam locomotive.¹

This has been done since Rocket's time by the use of stays.  These are metal rods, threaded at each end and screwed into threaded holes drilled and tapped in the inner and outer fireboxes.  The stays are placed at around 3-4 inch pitch and, after screwing in place, the ends are beaded over like rivets creating this appearance:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-140624144135.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142523)


A typical standard gauge locomotive's boiler will probably have over 1,000 stays.  A large boiler, like that used on the BR 'Britannia' 4-6-2 engines, has about 2,500 stays.

The narrowest water spaces around the inner firebox, at the sides and by the backplate in which the firehole is placed, are around four inches wide. Not that big when one thinks about it. Firebox side stays were traditionally made of copper with 'monel metal' (put simply, a nickel-copper alloy) being much used in later years.² 

At the bottom, the inner and outer fireboxes are separated by a large forging called the foundation ring.  It's not really a ring - more of a square or rectangle with rounded corners.  The foundation ring and the firebox sides have holes through which rivets are hammered home to secure the parts together.  The foundation ring also has bearers for the firegrate and attachments for the ashpan.

Once again, George's picture is of enormous help.  The 'Merchant Navy' class has a sophisticated firebox shape and the inner firebox, unusually for British practice, was made of steel.  But the fundamentals are the same as I have described.  The outer and inner fireboxes, and the side stays, can be seen.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-140624151350.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142525)


¹  The integrity of the firebox stays is essential for the safe operation of a steam locomotive.  As you know, I enjoy quoting the late LTC Rolt and this, from Railway Adventure is pertinate:

'[...] despite her appalling condition, Talyllyn had to be steamed and sent out to her [Dolgoch's] rescue.  This successful salvage operation was destined to be the last duty performed by Talyllyn, and those who have subsequently viewed the ominous bulge in the side of her firebox which betokens broken stays, or investigated a smoke-box tube plate which consists of more scale than plate, are of the unanimous opinion that he was a brave man who steamed and drove her on this last journey.'

LTC Rolt, Railway Adventure, Country Book Club, London, 1962. p38.


² The suitability of copper as a strong, but slightly elastic, material for side stays did not prevent locomotive engineers from experimenting.  Mr HA Hoy of the Lancashire & Yorkshire Railway devised his own copper/zinc/iron alloy and claimed it was stronger and 'perhaps' more elastic than copper.  It actually had very little elasticity leading to problems with cracked and broken side stays and, eventually, 0-8-0 No. 676's spectacular boiler explosion near Knottingley on 11 March 1901*.  Both enginemen were killed instantly.  Live steam is a hazardous thing. 


* For further details on the Knottingley boiler explosion and much else, I recommend the late CH Hewison's Locomotive Boiler Explosions, David & Charles, Newton Abbot, 1983 ISBN 0-7153-8305-1.  This is an invaluable book and I'm sure I'll refer to it again.  No. 676's explosion is on page 110 et seq.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerio

John

Fascinating stuff as always, John. I hadn't come across the 'Elizabethan Express' video before, but that was excellent. Superb shots of Silver Fox from another train alongside! And wasn't everybody thin in 1954! We all ate less and got around on our own two feet.

Many thanks!

Cheers,

Chris

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 17


Hello Chums

Let's show off.  You know that old thing about no-one knowing two famous (non-fictional) Belgians?  We steam enthusiasts do and we are about to meet one of them.

We were discussing firebox stays and, conveniently, the side stays are pretty much horizontal as the inner and outer firebox sides and backplate are reasonably parallel.  The top of the inner firebox  is, as the name suggests, like the top of a cube.  But, for the first sixty years of the Stephensonian locomotive in Great Britain, the outer firebox was rounded.  Like this:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-150624192835.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142579)


As you can imagine, staying the flat-top of the inner firebox (locomotive people call this the 'crown sheet') to the curvaceous outer firebox required some ingenuity.¹

Which leads us to M. Alfred Jules Belpaire, Chief Mechanical Engineer of the Belgian State Railway.  Although Belgium had a mining industry - as the BEF clearly saw in August 1914 - much of the coal was of poor quality and, from 1860, M Belpaire worked to produce a long firebox which could make the most efficient use of poor fuel.  By 1864 he had developed his flat-top Belpaire firebox which enabled the use of simple vertical stays for the crown sheet.

The first boilers with a Belpaire firebox constructed in Great Britain were made in 1872 by Beyer, Peacock and Co. for some 2-4-0 locomotives the firm built for use in Belgium.  Which makes us wonder which was the first British railway to introduce the 'New Look' as a consequence of the use of a Belpaire firebox.  Any ideas?


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-160624103309.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142611)

The New Look is personified by  Midland-built '2P' No. 40 for the Somerset & Dorset Joint Railway and the traditional outline is seen on Southern, former London & South Western Railway, 'T9' No. 301.  Templecombe on the Micro Layout? 

**
 

There was an early application of a flat-topped outer firebox on 0-6-0 locomotives introduced in 1866 by William Bouch on the Stockton & Darlington Section of the North Eastern Railway.  This firebox used direct vertical crown sheet stays, made of iron. Mr Bouch's firebox differed from the Belpaire type in that the flat-top of the outer firebox was lower than the top of the boiler barrel.  This type of firebox was not adopted elsewhere.

In Great Britain, the true Belpaire firebox had to wait until 1891 when it was adopted by Thomas Parker on the Manchester, Sheffield and Lincolnshire Railway for his '9F' 0-6-2T locomotives, later LNER class 'N5'.² Mr Ahrons suggested one of the railway's draughtsmen had previously been with Beyer, Peacock and Co.³

Sir John Aspinall on the Lancashire & Yorkshire Railway and William Dean on the Great Western Railway adopted the Belpaire firebox in 1897 and many other railways followed. But not all as we'll see in the next postington in this series.


¹ Normally by using what are called girder stays - eight or so longitudinal girders running, about four inches apart, across the top of the inner firebox crown sheet and secured to the outer firebox by drop links.  Later on, direct stays were used, those in the centre being of a considerable length.  We'll return to this.

² Mr Parker built three prototype engines with the Belpaire firebox, Nos. 7,47 and 171.  The MS&L classified these '9C', with the production locomotives being '9F'.  After the Grouping, they all became LNER Class 'N5'.

³ EL Ahrons, The British Steam Railway Locomotive 1825-1925, Locomotive Publishing Company, London, 1927 p.310


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toddle-oo

John

Excellent John, I have always taken the term "Belpaire! for granted or as read without actually realising or understanding what it is.

All the very best,

Tim

Another excellent installment John. The Pennsy in the US used Belpaire fireboxes too, I think because some of their coal was poor (though I am unsure of this as they had a lot of Anthracite in Pennslyvania). When I first saw pictures of the famous K4s I immediately saw the similarity to the firebox from the GWR locos I was used to.

@grumbeast

I believe the Pennsy K4 boiler  (and the whole design?) was used as inspiration for the first Gresley A1 boilers, using similar dimensions but within the UK loading gauge.

But, noticeably, the A1s retained a round top firebox, not Belpaire.

Source-"Nigel Gresley-locomotive engineer" by F.A.S. Brown.

Martyn

Hadn't realised the Belpaire firebox wasn't in use in Britain until 1872, very informative John  :thumbsup:




Ed

 

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 18


Hello Chums

A Pause to State the Obvious

Before continuing our discussion regarding locomotive boilers and, hopefully, getting (eventually) to the engine parts of a steam locomotive, there are couple of points I should like to make.  Stating the obvious, I'm afraid, but, I think, important for us to remember.

The first is just how quickly the Stephensons developed the steam locomotive from Locomotion No. 1 of 1825 to Planet of 1830.  The former a typical 'steam dinosaur' and the latter the foundation for just about every steam locomotive that followed.  Such a pace of technical development in peacetime is truly remarkable.


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British steam locomotives after Planet, seen in the picturingham, were mostly well-made, efficient and reliable.  And, often, particularly pretty.  But, as regards innovation, that passed mostly to others in Continental Europe and the USA, with a late flowering in Argentina and South Africa.

We have recently encountered the brilliance of M. Giffard and M. Belpaire.  There will be others soon.  Very soon.

I won't presume to say there were no innovations in Great Britain after 1860, when Messrs Markham and Kirtley on the Midland worked out how to burn coal without being anti-social.  But, there were surprisingly few.  Those that seem significant to me are the Gresley/Holcroft conjugated valve gear, and the Fairlie and Garratt locomotives.  The double Fairlie type being the ancestor of today's bogie diesel and electric traction.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-170624095550.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142625)

[You know how politics is not allowed to be mentioned on our FabulousForum (rightly, in my view), well I'm going to mention it.  Even although the Garratt locomotive was a British invention and Beyer, Peacock & Co of Manchester held the patents, the British didn't always get things their own way.  This 2-6-2+2-6-2 Garratt was built by Hanomag of Hanover in 1927 for the South African Railways.  There was a strong anti-British sentiment in certain regions of South Africa at the time which led to a preference for business to be placed elsewhere.  The South African authorities considered it politically expedient to allow this.  Now in active retirement, she is used on the Vale of Rheidol Railway at peak traffic times.  And, hopefully, the 20th Century politics associated with her construction have been consigned to history.]


Great Britain is a small island with a varied topography and, even in the early Nineteenth Century, well-populated with long-established patterns of land ownership and routes of communication.

People building the railways in the great 1830-1860 boom tended to have contemporary trains in mind.  The exception was IK Brunel with the Great Western and associated broad gauge railways.  Although, as time went on, it became clear gauge between the rails wasn't really the limiting factor.  Loading gauge was.  In other words, how high or wide could you build your locomotive before it bashed something.

And, in our busy little island, there was a profusion of bashable things.  Overbridges, high platform edges, tunnels, engine sheds, signal gantries and suchlike, and platform canopies.  Many of which were built with locomotives like Planet and its immediate successors in mind.

Also significant was the weight that the civil engineer would allow his bridges and other structures to bear.  And civil engineers revelled in caution - even after the 'Rude Mechanicals' tried to help them understand the significance of 'hammer blow'.

As we return to our story, it will be very obvious how much the later steam locomotives, which we think of as so typically British, owe to overseas engineers.  Perhaps a little lesson for those that claim only to be interested in British locomotives or railways.

*

In conclusion, I'd like to express my thanks to everyone who leaves a 'reaction' or adds a post to the thread.  It is difficult to gauge how to pitch these posts and your kind responses give me a valuable insight into how well I'm managing.  Thank you!


'N' Gauge is Such Fun

Many thanks for looking and all best wishes.

Cheerie-bye

John

John,

Your posts are always welcome and a very good read!

All the very best,

Tim

Please continue to both educate and entertain us John.

Thanks for the history lesson John. Fascinating insight as ever

Chris

Big congratulations to John for this excellent series of posts; may it continue!
I have learnt so much about the history of steam locos from the posts, and am eagerly waiting for those yet to come. Please carry on John.
KR

 :thumbsup:  :thumbsup:

Thanks for the thread and postinghams, John.

Although I've had a deep interest in steam locos for (far too) many years, I'm still learning!

Martyn

Brilliant, both entertaining and informative - please keep up the good work  :thumbsup:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 19


Hello Chums

Righty-oh, after the pause to state the obvious, on with the series and thank you very much for all those lovely, kind posts.

I have described the Belpaire firebox in its simplest form, effectively a squarish inner firebox inside a larger squarish outer firebox.  I think the ex-Midland '4F' 0-6-0 shows this arrangement well, with the large flat sides of its outer firebox cladding sheets.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-180624110115.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142652)


But not all Belpaire fireboxes are created equal and I suggest you have a close look at the one on a large Great Western Railway design-influenced locomotive to observe the complex shapes originated by Mr Churchward and employed later, with detail variations, by others.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-180624110141.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142653)


The side plates have gentle curves to permit free circulation of water around the inner firebox.  The firebox also tapers from the front to the back which permits wider cab front windows.  Finally, the firebox top slopes down from front to rear, which greatly reduces the risk of the rear of the crown sheet being exposed when the water in the boiler runs forward during braking.  Mr Churchward mentioned this last feature during a discussion on a paper entitled American Locomotive Practice at a meeting of the Institution of Civil Engineers (ICE) on 31 March, 1903.  I thought it would be a wizard wheeze to see the great man's words, spoken over 120 years ago:

"[...] the sloping top to the firebox is practically a necessity in such long boilers as are now used with 4-4-2 or 4-6-0 engines, and especially with the 2-6-2.  A boiler is now obtained with a 15 ft. or 16 ft. barrel, and perhaps a 9 ft. box.  When the brake is applied, the water in these long boilers runs to the front end to such an extent that the back of the roof-sheet is quite uncovered; and by dropping the back of the roof of the box 3 in., the benefit of 3 in. of water is obtained when the brake is applied."¹

Mention of American locomotive practice reminds us that Mr Churchward was much influenced by this, as was another British locomotive engineer, whose contribution we will discuss in the next postington in the series.

¹  Mr Churchward's comments at the meeting were recorded by the ICE and published at the time.  Mr HAV Bulleid reproduced extracts in his Master Builders of Steam, Ian Allan, London, 1963.  A splendid book, written by a locomotive engineer.  The book's preface is by Sir William Stanier, HG Ivatt (the author's uncle) and OVS Bulleid (the author's father). 

*

A note on the picturinghams.

'4F' 0-6-0 No. 4232 is an old ProperlyPoole Graham farish model and I think she captures well the look of the prototype.

'Castle' 4-6-0 No. 5051 Earl Bathurst (sometimes Drysllwyn Castle, her name in 1936-37, prior to renaming) is a Great Western Society locomotive.  She was photographed at Toddington on a sunny day.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

Thanks again, John.

Possibly anticipating part of your posts, if the crown sheet mentioned above was exposed due to low water level for any reason, then there was serious risk of distortion or even collapse, resulting in an explosion.

To counter this, a lead fusible plug was placed in the crown sheet which would melt and thus allow the water in the boiler to warn the crew.

Richard Hardy, when shedmaster at Kings Lynn (I think) tells of going into a firebox when the loco was still in steam to cure a weeping plug; this was strictly forbidden, I think, but the alternative was cancelling a train.

Martyn

later;

Just looked it up; he was at South Lynn (ex M+GN), and it was one of his boilermakers who went into the firebox to effect the repair.

M

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 20


Hello Chums

We have spent rather a lot of time on the Belpaire firebox.  Especially in its form developed by Mr Churchward, it allowed 'greater water area and steam volume for steam release at the point of maximum evaporation'.¹

By the time of the Grouping in 1923, most of the major British railways used the Belpaire firebox to a greater or lesser extent.  Two which didn't were the North Eastern and the London & South Western.

After the Grouping, its use was pretty much universal on the LMS and GWR.  The Southern was interesting because its designs derived from Mr Maunsell's work on the South Eastern & Chatham used it, but those derived from London & South Western designs, such as the 'King Arthur' 4-6-0, had a round-topped boiler.  The new 4-6-0  'Lord Nelson' class used a Belpaire firebox, but the SuperSuccessful 4-4-0 'Schools' class didn't.  Because its firebox was based on that of the 'King Arthur'.

I try to include at least one picturingham in these postingtons and I like the 'Schools' class.  But I don't have a photograph of one.

Brainwave!

Friend of Poppingham @Ali Smith is a scholar and a scholar (albeit not necessarily in that order) and he and Rob have the absolutely fabulous Vermouth layout.

Bingo! 


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-190624131433.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142670)


It is understood Mr Maunsell would have preferred to use a Belpaire firebox in the 'Schools' class and that the first design proposal used a firebox based on that of the 'Lord Nelson' class.  However, the restricted loading gauge of the Hastings route, especially Mountfield tunnel, required a width of no more than 8' 6 1/2", with, importantly, only 7' 7" width at cab gutter level.²  This meant the side sheets of the cab had to be turned inward from about half-way up - such a distinctive feature of the class.  The very narrow cab width, coupled with a Belpaire firebox, would not have given sufficient room for cab front windows of a practicable size.  So the same round-top firebox as on the final series of 'King Arthurs' was used.  Ali's phabulous photograph demonstrates these features to perfection, so you can see the reason the engine has a round-top firebox is so the enginemen can see.³

One other major pre-Grouping company did not use the Belpaire firebox - the Great Northern - and its practice became very influential on the LNER.  Hopefully, we'll think about that in the next part of this series.

*

The firebox is where the potential energy from the coal is transformed into heat energy which, in turn (due to the magical properties of water), becomes kinetic energy and Mallard goes at 126mph.  I'll bet Tommy Bray was kept jolly busy that day. 

It's obvious, but the bigger the grate, the more heat energy can be obtained.

In early Twentieth Century British practice, there were two fundamental constraints on grate size.  Firstly, the distance between the frames in which to fit the firebox - please remember the four inches or so water space between the inner and outer fireboxes and that the track gauge is not the distance between the inside of the frames.  If width is constrained - and three feet is pretty much the maximum grate width for a firebox that fits between a standard gauge locomotive's frames - increased grate area can only be achieved by additional length.

If the only way to increase grate area was greater length, the second constraint was how far an average, tired, fireman could fling⁴ a shovelful of coal.  At 80mph!

Here's Mr Churchward on the subject, speaking at the ICE meeting mentioned in Part 19:

"It has been found on the Great Western, that both in the French engines and in our own engines, with a proper slope of the boxes, a 9 or 10 ft. box can be fired without any difficulty whatsoever.  As a matter of fact, some of the 9 and 10 ft. boxes that are running at present are more easily fired and easier to work on the foot-plate than a number of the old 6 and 8 ft. boxes cut on the straight.

If you will keep in your mind's eye for a moment the short flat portion that goes over the trailing axle in the ordinary long box and then the considerable bit of slope that runs down, you will find that 75 per cent, I should say, of the coal is put on to the the flat part of the box and the rest fed down,  There is really no trouble whatsoever in this respect, and the difficulty of firing is no argument to my mind against long boxes at all."


Please, someone, correct me, but I believe the GWR 4-6-0 'King' class has the largest grate area of any British steam locomotive, with the firebox between the frames, at 34.3 sq ft.  This required a firebox no less than 11' 6" long.  Remember King George V with the bell the Baltimore & Ohio Railroad presented to her which is proudly carried on the buffer beam?  I'm given to understand that young cleaners, aspiring to be firemen, were challenged to propel a shovelful of coal so powerfully that it hit the tubeplate of the firebox with sufficient force to ring the bell.  Impossible, of course.  Except that old hand firemen could do it every time.⁵

More importantly, and I do not write from experience, but GWR firemen used a very deep fire below the firedoor.  I expect they also put a few shovelsful 'down the sides' and in the back corners of the firebox.  There was probably little need to fire to the front of the 'box, as Mr Churchward said.  However, on other railways, not using Welsh steam coal, firing techniques could be different with a thinner, more even fire preferred.

The Southern Railway's 4-6-0 'Lord Nelson' class was next in grate area, I think, at 33 sq ft.  And 'Nelsons' were believed by many enginemen to be difficult to fire.  Perhaps a firebox length of 11-12 feet or so was approaching the limit for hand firing.  Which would give a theoretical maximum grate area, for a firebox between the frames, of around 35 sq. ft.

I won't discuss further the pros and potential cons of sloping grates, as mentioned by Mr Churchward, here as this is not relevant to 'N' gauge.

If a larger grate area was consider desirable, how could it be achieved? If all goes according to what I call a plan, the next part will consider how this can be done - a 50 sq. ft. grate anyone?

Time, now, to prepare for the next part by crossing the Atlantic to the USA where, as @grumbeast helpfully mentioned, the Pennsylvania Railroad used the Belpaire firebox.  As did the Great Northern Railway (unlike our one!).


¹  I pinched the phrase from Mr ES Cox, Executive Officer (Design), Railway Executive.  It's in his report Proposed New Standard Locomotives, of 13 December, 1948.

²  BR dealt with Mountfield tunnel in the 'seventies by singling the line through it.

³ Special thanks to Ali and Rob for their scholarly contribution.

⁴ Presumably during that vicious climb in the down direction from Carrbridge to the Slochd, it would be a Highland Fling.

⁵ I understand firemen used a length of string, looped round their foot, to ring the bell on 'KGV'.  No ideal if its true but a nice story.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

another abs  fascinating account !

Quote from: martyn on June 18, 2024, 12:26:24 PMThanks again, John.

Possibly anticipating part of your posts, if the crown sheet mentioned above was exposed due to low water level for any reason, then there was serious risk of distortion or even collapse, resulting in an explosion.

To counter this, a lead fusible plug was placed in the crown sheet which would melt and thus allow the water in the boiler to partly douse the fire and warn the crew-who may have had difficulty getting off the footplate if the loco was at speed!

Richard Hardy, when shedmaster at Kings Lynn (I think) tells of going into a firebox when the loco was still in steam to cure a weeping plug; this was strictly forbidden, I think, but the alternative was cancelling a train.

Martyn

later;

Just looked it up; he was at South Lynn (ex M+GN), and it was one of his boilermakers who went into the firebox to effect the repair.

M

I did something similar in 1979 when King George V failed on a Friday Railtour and that night 5900 Hinderton Hall was brought back to Didcot I went into the firebox next morning with 40 PSi of steam still on and gave it a proper clean round knocking the "corks" off the Crown stays and brushing down the Brick arch before cleaning the grate Whilst one of our drivers kept an eye on me to make sure I was ok. then getting out and emptying the ashpan before handing over to the lighter up as the Hall was to cover the Sunday railtour that the King had been due to take. I was offered a place on the service crew as a result of the job I had done, but had to decline as I was due to take my shunters exam the next day! so next morning we saw the Hall depart then I took the exam and passed out as a shunter having endured a grilling under a BR inspector and was able in my new position to see the Hall back on site after a successful tour - Happy Days!

Regards,

Alex

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 21


Hello Chums

The answer to a greater grate (sorry) area without breeding superhuman firemen was to go wide and that is what John E Wooton, General Manager of the Philadelphia & Reading Railroad did in 1877.  You see, the eastern Pennsylvania anthracite mining industry produced a by-product, after the anthracite was washed and graded for domestic use.  The leftovers were called 'culm' and were cheap.  Culm burned slowly and required a wide, shallow fire.  Mr Wooton's firebox was very wide and its initial use was in these curiosities 'Camelback' or 'Mother Hubbard' locomotives, where the engineer was placed on top of the boiler and the fireman was, if he was lucky, in a cab at the firebox end.  This was because the first Wooton fireboxes were so wide that the engineer would have no forward view from a conventional cab.

The much more agreeable US loading gauge permitted the Wooton firebox to be used on types like the 4-6-0 but the more constrained British loading gauge was less amenable to such liberties being taken - that is until the BR 'Standard' '9F' 2-10-0 came along.  Which meant a proper wide firebox could only be achieved, normally, within the British loading gauge, by the use of a trailing truck.  Especially as the requirement for high continuous combustion was for large-wheeled express passenger locomotives.  And Americans would show the way.

The 'Camelbacks' had many detractors¹ and US railroads found a compromise with conventional cabs being used with wide fireboxes, whose use was spreading further than the 'anthracite roads'.  A good example is the first bituminous coal-burning 4-4-2, built by Schenectady for the Chicago & North Western Railroad in 1900.  Eventually the class, which excelled on fast passenger work, totalled 91 engines.  The wide firebox was supported by the rear truck.

The first 'real' standard gauge 'Pacific' 4-6-2, there had been early narrow-firebox oddities, was built in 1902 by Brooks for the Missouri Pacific Railroad.²

I was wondering if it might be a jolly jape to include a picturingham of a massive American locomotive with a wide firebox.  @Ali Smith read what passes for my mind and sent this SuperSpiffing photograph of a Pennsylvania Railroad 'M1a' 4-8-2.  This class was introduced in 1930 and some engines survived to the end of steam on the Pennsy in 1959.  The use of the Belpaire firebox - a Pennsy specialty - was uncommon in the USA.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-200624092630.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142681)

Pennsylvania in Dorset - Moonshine Vermouth?


Most British 'Atlantic' 4-4-2 classes did not capitalise on this advantage of their trailing truck.  In fact, Mr Churchward built some 'Atlantics', for comparison purposes with 4-6-0 equivalents, that could be converted into 4-6-0s.  They were.  Rear coupled wheels, rather than a truck, gives better adhesion at starting and under full power when a locomotive tends to 'sit back' on its rearmost wheels. Skittery Bulleid 'Pacifics' demonstrate this phenomonen to perfection.  It can be partially overcome by complex compensated suspension systems but this was rare in Great Britain.

That, in my view, much under-rated locomotive engineer, HA Ivatt, introduced his second 'Atlantic' class, with a wide firebox this time, to the Great Northern Railway in 1903 and these were capable of superlative performances.  The grate area was 30.9 sq. ft.  His assistant, Mr Earle Marsh, when appointed Locomotive Superintendent of the London, Brighton and South Coast Railway, took a set of the 'Large Atlantic' drawings Brightonwards and a near-identical and similarly puissant class ensued.  The Bluebell Railway has just finished building another example.

Here's what Mr Churchward had to say about wide firebox 'Atlantics' at the ICE meeting referred to in Part 19.  The paper being discussed was entitled American Locomotive Practice:

"Probably, to English locomotive-engineers, the part of the paper which deals with boilers is the most interesting; especially the reasonably wide firebox which thr author has described. An express engine with a similar box has just been put on the Great Northern Railway by Mr. Ivatt, and I trust it will have a good trial in England. I think English locomotive-engineers are within measurable distance of adopting it, and I am sorry that the French 'Atlantic' engine, which is to be put on the Great Western Railway, is not fitted with it - but I am taking this engine as it stands."³

Other British railways tended to ignore the advantages of the wide firebox for a while, although Mr Churchward used one on his one-off 'Pacific' The Great Bear with a grate area of 41.79 sq ft.

The wide firebox's time would come a few years later.  Except on the Great Western (Mr Churchward's The Great Bear of 1908 apart), which was blessed with wonderful Welsh steam coal and SuperStrong firemen.  Mr (later Sir Nigel) Gresley, who succeeded Mr Ivatt on the Great Northern and was appointed as first Chief Mechanical Engineer of the LNER, was a convert to wide fireboxes and used them on several classes, including his 'Pacifics', and 'V2' and 'V4' 2-6-2 classes.  Here's a picturingham of a 'V2' 2-6-2 showing her wide firebox (41.25 sq. ft. grate area - that's the same as an 'A4' 4-6-2) placed neatly over the rear truck:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-180624161551.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142656)


The next postington will, hopefully, consider why the LNER was something of a loner with regard to its fireboxes.  And it's not just to do with width.  The LMS and the Southern (eventually) also used wide fireboxes. And the LNER also deserves another honourable mention which we'll get to at some point. 

¹ The final 'Camelbacks' were built for the Lehigh & New England Railroad in 1927.

² But the first real 'Pacific' type was built a year earlier by Baldwin in 1901.  For service in New Zealand and, therefore, narrow gauge (3 ft. 6 in.). 

³ The French locomotive Mr Churchward mentioned was four-cylinder compound 4-4-2 No. 102 La France which entered service in October 1903.  Two slightly larger French 'Atlantics' were purchased by the GWR in 1905.  The results of this open-minded experiment (how many British locomotive engineers would have persuaded their Boards to buy three locomotives of an innovative design for trial?) were that the 4-6-0 gave better adhesion, especially on the West Country banks, and that compounding gave no advantage in Great Western service.  Given Mr Churchward's strong support of long, narrow fireboxes which I quoted in Part 20, his interest in wide fireboxes as well shows the great man's open and enquiring attitude to steam locomotive development.

Many thanks to Ali for the photograph of the 6743.


'N' Gauge is Such Fun

Many thanks for looking and all best wishes.

Tickety-tonk

John

I'm learning loads but, sadly, retaining little :*(
Good job I have this thread to refer back to :)

SEE MY NEXT POST FIRST!

I am now a bit doubtful after reading this, John, but I'm sure that I have read that the Wootten firebox was designed specially for a low firing rate (amount of coal, or culm per hour per square foot of grate), and the grate developed by the GNR/LNER was a wide firebox, but not Wootten pattern. IIRC, the Wooten fire box was wide to allow each shovelful of coal to burn thoroughly over a relatively long period.

Wikipedia seems to agree with you, however;

https://en.wikipedia.org/wiki/Wootten_firebox

I have no idea where I read that the British version of the wide firebox was not Wootten pattern; certainly from accounts, the GNR Atlantics had quite a high firing rate. I don't know the technicalities of the Wooten pattern, but the wide grates in the UK were of a conventional design, but enlarged to go across rather than within, the loco frames.

But, of course, I could well be wrong, in which case apologies and ignore this post!

Martyn

later;

This article is an American view, and definitely says the conventional fire was too strong for the culm dust to burn;

https://www.american-rails.com/wootten.html

Later again;

this article has a quite technical answer about the Wootten fire box written by pjb and near the bottom of the replies;

https://www.trainorders.com/discussion/read.php?10,581983

I'm replying to my own post;

I may have misunderstood your post, John, as you did not imply that the Wootten pattern ws used on the GNR/LNER, but just the wide pattern across rather than within the frames.

Very sorry..... :(  :(  :(

Martyn

Quote from: martyn on June 20, 2024, 11:50:11 AMI am now a bit doubtful after reading this, John, but I'm sure that I have read that the Wootten firebox was designed specially for a low firing rate (amount of coal, or culm per hour per square foot of grate), and the grate developed by the GNR/LNER was a wide firebox, but not Wooten pattern. IIRC, the Wooten fire box was wide to allow each shovelful of coal to burn thoroughly over a relatively long period.

Wikipedia seems to agree with you, however;

https://en.wikipedia.org/wiki/Wootten_firebox

I have no idea where I read that the British version of the wide firebox was not Wootten pattern; certainly from accounts, the GNR Atlantics had quite a high firing rate. I don't know the technicalities of the Wooten pattern, but the wide grates in the UK were of a conventional design, but enlarged to go across rather than within, the loco frames.

But, of course, I could well be wrong, in which case apologies and ignore this post!

Martyn

later;

This article is an American view, and definitely says the conventional fire was too strong for the culm dust to burn;

https://www.american-rails.com/wootten.html

Many thanks for this, Martyn.

My understanding is that the 'conventional' wide firebox evolved from the Wooten type in the USA as railroads burning bituminous coal sought larger grate areas.  I understand many of the 'pure' Wootten fireboxes had double fireholes.

I also believe there is a tendency to call any wide firebox 'Wootten' - certainly one sees that description with LNER 'Pacifics'.

The wide firebox came quickly from the US to Great Britain - this adoption of overseas practice in Britain is one of the wider points I'm attempting to make.

I leave more out of these posts than I include so I'm glad your reply has given me an excuse to mention another British use of the wide firebox contemporaneous with Mr Ivatt's 'Large Atlantic'.  And it also did not have a training truck.  The engine was, of course, the Great Eastern 'Decapod'.  I left it out of my text as it was an evolutionary dead-end but it's nice to give it a mention.

Also nice to mention are M. Flamme's locomotives in Belgium, with 50 sq. ft. fireboxes in the Edwardian era.  The Lancashire & Yorkshire thought seriously about building a version of the Flamme  2-10-0.

Thank you for the weblinks which I'll look at with interest. I tend to write these posts from memory with a lot of subsequent checking using books and magazines of which I have far too many.  I don't normally look at the internet so this will be interesting.

Thanks again and all good wishes.

John

PS Thank you for your second post which our FabulousForum told me about when I went to press the 'post' button.  I'll still post this as we both find the 'Decapod' of interest.  I think you also have a nice picture of her.

Thanks, John.

I agree that there are many references to the GNR/LNER design of wide firebox as fitted to the Atlantics and Pacifics as 'Wootten'.

Other accounts just say 'wide' firebox; but at least one account I have read the author emphasises that it is wide but NOT Wootten....

I really don't know........and thanks again for the honorary mention of Decapod!

Martyn

A longish quote from the RCTS : Part 3A of 'Locomotives of the LNER' ('the green bible').

Talking about the Ivatt class C1 (on both the GNR and LNER) Atlantics;

'This was not the first time that an engine with a wide firebox had run on the GNR, for about 1882-4 an American 4-2-2 Lovatt  Eames (Baldwin Works no. 5000) made a few trips to demonstrate the Eames vacuum brake system. This engine had a special wide firebox designed by J.E. Wootten to burn anthracite dust which was too fine for normal use. A large shallow grate (56 sq ft) was used because the firing rate had not to exceed 20lb per hour per sq ft. There was thus no direct connection between a Wootten firebox and Ivatt's wide firebox though the term Wootten afterwards mistakenly became associated with the ordinary wide firebox'.

End quote.

Bold emphasis not in original, highlighted by me.

Incidentally, I've never seen the wide firebox LMS or SR boilers referred to as 'Wootten'. And again, I emphasise that Train Waiting/John does not say the GNR/LNER wide fireboxes were of the Wootten pattern, I misunderstood part of his post.

Martyn

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 22


Hello Chums


At the time of the Grouping, on 1 January 1923, the Belpaire firebox was used, to a greater or lesser extent, by most British railways apart from the London & South Western, North Eastern and Great Northern.  The wide firebox was much less common - its use being confined to the Great Northern, North Eastern and London, Brighton & South Coast.

After the Grouping, the Great Western carried on in the narrow Belpaire firebox tradition established Mr Mr Churchward.  The LMS under George Hughes and, later, Sir Henry Fowler, pretty much universally used narrow Belpaire fireboxes for new construction. The Southern, under Richard Maunsell, favoured Belpaire fireboxes (Mr Maunsell's technical team had carefully chosen men from Swindon and Derby), but as we have seen earlier continued with round-topped fireboxes for locomotives derived from London & South Western designs.

Which leaves the LNER as the odd one out.  Strange, that - the GWR is so often though of as being the oddity, but in the matter of boilers in 1923, it was pretty much in line with conventional thinking.

The LNER, under HN (later Sir Nigel) Gresley and his successors pretty much restricted new constrution to locomotives with round-top fireboxes, although Mr Gresley was open-minded enough to continue construction of good pre-Grouping types which had Belpaire fireboxes.  As time went on, certain pre-Grouping locomotives with Belpaire fireboxes were reboilered with round-top fireboxes.  And the wide firebox could only be seen, for nine-and-a-half years from  January 1924, on the LNER.¹

LNER classes with wide fireboxes were -
4-6-2-2: 'W1' (as rebuilt) (Gresley)
4-6-2: 'A1' (Gresley), 'A2' (Sir Vincent Raven), 'A3' (Gresley), 'A4' (Gresley), 'A1' (Peppercorn), 'A2/1', 'A2/2', 'A2/3 (Thompson) and 'A2' Peppercorn
2-8-2: 'P1' and 'P2' (Gresley)
2-6-2: 'V2' and 'V4' (Gresley)

Quite a list - have I forgotten any?

As is well-known, Sir Henry Fowler was promoted horizontally and WS (later, Sir William) Stanier was appointed Chief Mechanical Engineer of the LMS with effect from New Year's Day, 1932.  Barely eighteen months later, the first two of his 4-6-2 'Princess Royal' class appeared.  These prototype locomotives had a certain 'elongated Swindon' (with perhaps a hint of an updated The Great Bear?) look about them (Sir William had come from the Great Western), but with a wide Belpaire firebox above a rear Bissel truck.

A couple of years later, ten more were built and these benefitted from design modifications made in the light of experience with the two prototypes.  Also in 1935, a fascinating varient of the 'Princess Royal' class, No. 6202 - unnamed but usually called 'Turbomotive' appeared.

Then, in 1937, Sir William's masterpiece, the 'Princess Coronation' 4-6-2 class was introduced.  Essentially a much improved 'Princess Royal'.  Thirty-eight were built, including the final two in 1947/48 with clever detail modifications by that most practical engineer HG Ivatt.  These locomotives had an enormous wide Belpaire firebox with a 50 sq. ft. grate area (the 'Princess Royal' class was 45 sq. ft.) 

Although this was a massive grate area for British practice at the time, Sir Nigel Gresley's 'P2' 2-8-2 of 1934 also had a 50 sq. ft. grate area.²


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-210624114814.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142716)

Just look at that enormous firebox on No. 6233 Duchess of Sutherland.  Just the thing to produce the power for the banks on the West Coast Route.  I was born too late to appreciate main line steam (I can only just remember it) but my late father took me, in a work's van, to the road outside Butlin's holiday camp at Heads of Ayr to see this magnificent locomotive.  I like my Graham Farish model of her, but it's of 'Far East' manufacture.  I'd swap it in an instant for a ProperlyPoole one.  With an additional bribe of some cash in a wee broon envelope.


And so to the Southern, when its locomotive orthodoxy was turned on its head in 1937 with the appointment of OVS Bulleid as Chief Mechanical Engineer.  His 'Merchant Navy', 'West Country' and 'Battle of Britain' classes introduced the wide Belpaire firebox to the railway.  These had grate areas of 48.5 and 38.25 sq. ft. respectively.  Also, most unusually, these classes had welded steel fireboxes.  Welding technology was developing at the time and Mr Bulleid took it to its limit.  The first 10 'Merchant Navy' boilers were replaced after only seven years and a special X-ray inspection technique was used to monitor the state of the welding in the others.³

After nationalisation, the Belpaire firebox reigned supreme for new 'Standard' engines, narrow for most designs, but wide for the 'Britannia', 'Clan', 'Duke of Gloucester' and '9F' classes.  The latter was originally schemed as a wide firebox 2-8-2 with 5 ft. 3 in. coupled wheels by ES Cox, but Robin Riddles insisted that, by reducing the coupled wheels to 5 ft., a 2-10-0, with much better adhesion, could be (just) accommodated within the loading gauge.

¹ GWR 4-6-2, No. 111 The Great Bear was withdrawn in January 1924 and rebuilt as a 'Castle' class 4-6-0, Viscount Churchill.  It is thought that little of the original survived the rebuilding.

² As did the rebuilt 'W1' in 1937 and the later Thompson and Peppercorn 'Pacifics'.  Whilst this figure was not surpassed for conventional locomotives in Britain, the LNER 'W1' 2-8-0+0-8-2 Garratt had a 56.5 sq. ft. grate area.  She was later converted to oil firing but this wasn't a success.  A Union Pacific 'Big Boy' had a 153 sq. ft. grate!

³ Not really relevant to 'N' gauge, the fireboxes also were fitted with thermic syphons to improve heating and circulation of water in the boiler.  Effectively, the colder water at the bottom of the boiler was circulated upwards through the thermic syphons.

*

Help please!

I soon will mention temperatures.  In steam days this was done in Fahrenheit and the sources use this.  Are you content for me to use ^oF, or would you find it easier to read if I use ^oC?


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerio

John

 

Quote from: Train Waiting on June 21, 2024, 12:13:05 PMI soon will mention temperatures.  In steam days this was done in Fahrenheit and the sources use this.  Are you content for me to use ^oF, or would you find it easier to read if I use ^oC?

Either suits me, John, but your excellent thread will now be inundated with replies to that question. Once you've decided, I can remove them for you as I think that would be cleaner

Farengrade or Centiheit, I don't mind. I am finding this series both interesting and informative and hope you will continue with it. There is a great deal of information out there about such matters as when no.1234 received the new type of safety valve, but not so much about how no.1234 worked or indeed how it went about its business.

Perhaps you could include the temperature conversion formula, which if I remember correctly isn't too complicated.

Another fine post John.

I am so glad you mentioned the LMS Princess Coronations.  While ostensibly a GW man given my place of birth I can't help but be in awe of the Duchesses and was able to recently procure one (in BR Maroon).  It is a testament to their effect on the local populace that I feel an affinity for the GWR even though I was born over 20 years after its demise!

Back to technical things, I think the grate area of UPs big boys is a bit like apples and oranges, one does have to remember that they did use automatic stokers, it would be simply impossible to fire such a monster by hand!

I was curious about the firebox size of other articulated locos of other companies and was surprised to discover that both the N&W y6bs and the DM&IR yellowstones have grates quite a bit smaller.  The y6b I get as it doesn't have the same tractive effort / HP as the Big Boy but the yellowstones are pretty much on par (slightly higher tractive effort at a whopping 140000lbs) but will a grate area of *only* 125sqft. I wonder why that is?

As for F or C, its fine, I have to endure those south of the border here insisting on using Fahrenheit all the time :)

Graham

Interestingly, the RCTS green Bible is critical of the 50 sq ft fireboxes fitted to the Thompson and Peppercorn boilers, and adds that 'Doncaster's whole [later] policy with boilers was wrong'. Without getting too technical (some of which I don't understand anyway), was that the firebox was producing too much heat for the small evaporating tubes to handle, and the superheaters were having to heat the steam to the required temperatures.

it was also stated after road tests that the large grates were wasteful of coal, as locos fitted with smaller grates could handle the trains with adequate steaming rates. Interestingly, the A4s with a 42.25 sq ft grate were much more economical in general; it was said that at times, the large grates were being fired 'just to cover all the firebars'. But then the A4s came out best of all the locos trialed in the 1948 exchanges.......

I've also read comments alluded to already; the original A1 boiler was effectively a scaled down Pennsy K4 one to fit the UK loading gauge. Further boiler development at Doncaster gradually departed from the ratios first used for the A1 boilers, seemingly not always to advantage.

And of course there is a subject about which I know little; the 'boiler horsepower' and the 'cylinder horsepower'. 
It was no good having a huge boiler and firebox if the cylinders could not effectively use the steam generated.

The RCTS History of the BR Standard Pacifics has a table of test results for the BR Standard tender locos, and principal express locos of the four regions, plus the Black 5. It gives boiler efficiency of ~70% for all classes tested, but cylinder efficiency of ~14%. I think it is the latter which shows just how inefficient the steam loco was, though things like compounding and re-superheating could add a few percent to the overall ratio.

Thanks again for another fascinating postingham, John.

Martyn

I'm old enough to have been taught both, so I don't mind F or C.
Fascinating series and like other I'm learning a lot,; again, as others I'm probably going to forget it quickly! I've book marked the thread and hope it stays available for years to come.
ATB

I think you may have forgotten one LNER wide firebox loco, John; the Thompson A1/1 rebuild of 'Great Northern'.

Martyn

@grumbeast

tractive effort was calculated based on a formula which included number of cylinders, cylinder diameter, cylinder stroke, 85% of boiler pressure, driving wheel diameter, and, usually, a 'constant' which was different for saturated or superheated steam.

See Google

The formula was slightly different between North American and European calculations.

This means that TE was not dependent upon grate size.

Martyn

As a physics teacher, the SI unit is Celsius, so that's what I'm used to. But I also agree with Mick to remove the replies (including this one), as we don't want them clogging up this superbly educational thread.  :thumbsup:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 23


Hello Chums

We are about to move from the firebox to the boiler and, before we do, a word or two about 'steaming' is in order.  And, no it is not a cautionary story about hard-working journalists leaving a Press Reception.

It's a term used by enginemen but I can't recall having seen a formal definition.

Let's suggest good steaming is the locomotive's boiler being able to maintain maximum working pressure, as and when required, with ease.  Even with an injector on and steam heat being provided to the train.

The basics of good steaming are airflow through the fire, efficient combustion, good draughting and efficient heat exchange from the consequences of combustion to the water in the boiler.

Poor steaming can result when one or more of these basics are not met.

This can be due to poor design (the LMS '5XP' 'Jubilee' class were bad steamers at first and there are many other examples), poor locomotive condition either due to ineffective maintenance or something going wrong when the locomotive is at work, poor quality coal, and inferior enginemanship, whether due to ignorance, tiredness, carelessness or laziness.

And one last reason for poor steaming - the locomotive was sulking that day.  As living things, they have their moods!

For the purposes of this series, we can discount most of these and focus on design.  Because this is the one that affects the appearance of our toy trains.

*

Thank you for your helpful posts and for your help regarding ^oF or ^oC. I now have a plan.

And please don't be concerned about remembering any of this - the threadingham will, hopefully, be here for ages although it might get 'buried' as this is a busy area of our FabulousForum.

Perhaps one thing to remember - George Jackson Churchward was probably the second most gifted locomotive engineer our country has produced.  I am enjoying quoting his words and am grateful to those who recorded and preserved them.

Oops-a-daisy; no picturingham yet.  I'll soon attend to that.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-230624091732.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142752)


No. 46115 Scots Guardsman at Carlisle in the rain.  A 'Converted Royal Scot', now with features derived from Churchwardian practice thanks to Sir William Stanier and HG Ivatt.  This class was one of the stars of the 1948 Locomotive Exchanges but had no effect on the design of the BR 'Standard' classes. 

She was in fine form on the down journey back to Lancaster over the Settle & Carlisle.  At Mallerstang, that three-cylinder 'fliffle-wuffle-flaffle' beat changed into something close to the famous 'Royal Scot roar'.  I was invited onto the footplate at Carlisle and the enginemen were impressed with her.  She was steaming well that day.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

Wonderful. :thumbsup:

After reading through this thread I can honestly say that I am no wiser than I was before.
I am, however, far better informed.
PW

I've posted on the Forum before somewhere about this, but I have a report somewhere reviewing the results of the 1948 loco interchanges.

I think it's by Cecil J Allen, and he says that the rebuilt 'Royal Scots' generally performed above their nominal power rating.

If I can find the report, I'll post a bit more (maybe?).

Martyn 

Quote from: martyn on June 23, 2024, 02:08:00 PMI've posted on the Forum before somewhere about this, but I have a report somewhere reviewing the results of the 1948 loco interchanges.

I think it's by Cecil J Allen, and he says that the rebuilt 'Royal Scots' generally performed above their nominal power rating.

If I can find the report, I'll post a bit more (maybe?).

Martyn

Many thanks to @martyn for this and please do.  It would certainly be of interest.

I have CJ Allen's book, The Locomotive Exchanges (Ian Allan, London, 1949) and here's a couple of quotes:

About the driver:

'[...] the 'Royal Scot' driver achieved feats of brilliance that I should barely have conceived possible with an engine of such dimensions [...]

About the engine and driver:

'Relatively to the moderate dimensions and weight and the simplicity of design of these 4-6-0s, in the most capable hands of Driver Brooker, I should be inclined to rate their best performances above anything else that I witnessed during the test weeks and, like those of the Southern engines, these were a a tonic indeed.  Moreover, the drawbar h.p. outputs of 1,750 to 1,800 exerted by the "Scots" on some of the climbs must surely constitute a record for any British 4-6-0 design of no more than 83 tons in weight.'

Praise indeed from 'CJA', an ex-GER and LNER man.

I'm fortunate +++ for this to have been Dr Tuplin's copy of the book.  'CJA' comes in for a barrage of pencilled annotations.  His 'no more than' in the quote ante gets circled and marked with a 'X'.

Even worse, earlier in the book, 'CJA's' use of 'extremely moderate' comes in for particular disapprobation with Dr Tuplin's use of a '?'.

If you are unfamiliar with the writings of the late Dr Tuplin, please ignore the last couple of paragraphs.  If you are familiar; you'll understand.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-B

John

The 'Scots' don't hang about even now........

(https://live.staticflickr.com/31337/50227716908_52871fa264_m.jpg) (https://flic.kr/p/2jwsbk7)46100 Royal Scot races through Leyland 15.8.20 (https://flic.kr/p/2jwsbk7) by Mick Hollyoake (https://www.flickr.com/photos/182878845@N04/), on Flickr

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 24


Hello Chums


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-240624095927.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142796)


At last... boilers!

Let's think about the 'kettle' analogy.  Much used and some railway enthusiasts appear to call steam locomotives 'kettles'.  I put water my kettle, boil it and then make coffee for Dame Joanna Lumley's morning visit to see my train set.

It then sits almost empty for a few hours until I refill it with fresh water, boil it and make a pot of tea for Jenny Agutter's visit in the afternoon.  That's a kettle for you: fill-boil-empty-repeat.  Sort of stop-start-stop.

It is better to think of a steam locomotive's boiler as a flow system with a variable throughput, unlike the fairly constant throughput in industrial or marine applications.  It's no use if the boiler goes 'off the boil' when it is being refilled with water and even less use if runs for a while until the boiler is empty and then needs to be refilled and boiled again - 'Mamod' steam traction engine, anyone?

The boiler must be able to produce steam, at its working pressure, whilst coping with the inflow of cold water, from the injector, to compensate for the steam that is, eventually, going up the chimney (unless the locomotive is one of these rarities, a condensing engine).

Nothing like my kettle, then, and those who use the analogy deserve our sympathy.

Possibly, the closest analogy in many houses is the 'combi' boiler which provides water at a (hopefully) steady temperature for the shower.  It's an imperfect analogy, but still a type of  flow system with a throughput.

My kettle is round with an empty space in the middle for the water, which is heated by a plate sort of contraption at the bottom.  Better than the old-style element which could get 'furry'. (But not here m'dear - between the Forth and the Tweed.  We have soft water.) Very limited 'heating surface'.

A locomotive's boiler is round, normally horizontal, unlike my kettle unless I have couped it again, and is anything but empty inside.  Since Rocket's time, it is packed with tubes, through which hot gasses from the fire pass, until about three-quarters of the way up.  Lots 'N' lots of tubes. The number varied with the boiler diameter - a North British 'Atlantic' of 1906 with a 5' 6" diameter boiler had 253.  A lorra, lorra tubes. Much better 'heating surface'.

Diameter - about that of the cardboard tube from a roll of lavatory paper - please see above.  My generation was 'Blue Peter' trained.  The picturingham below shows them 'in the metal'.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-240624095904.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142795)


We'll look into this in some more detail next time.  Might even have a formula - eek!

*

I hope you'll excuse the many liberties I have taken with simplification (over-simplification?).  Any experts wondering about tube numbers please note I have chosen a typical (if large) example from 1906.  We'll get to t'other stuff later.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-pip

John

I wondered why Joanna never answered my morning calls. At least I know to call in the afternoon now
 :thankyousign:

Yeah, I've had a furry kettle in the NE, and even in Australia.

I've had many furry tongues, though.  :uneasy:

Another great post in an amazing thread.  :thumbsup:  :beers:

For John's (and anyone else who is still interested) benefit, concerning the Royal Scots, some extracts from;

'New Light on the locomotive exchanges' by CJ Allen, published by Ian Allen in 1950. It is a supplement to 'The locomotive exchanges ' by the same author. It is a small (60 page) A5 size booklet.

Much of it is tabular results from the trials, broken down by loco type and route. Not all results summaries seem to be tabulated. It does have some background about when the trial trains were delayed by signals, heavy traffic, or whatever, which adversely affected coal and water consumption.

One really needs to study the tables to get a picture of the full results, but talking about the Royal Scots, CJA says 'the more one studies these figures, so much more astounding does the Performance on the rebuilt 'Royal Scot' seem.

' ...nowhere in the trials....did the Western Region 'Kings' approach such horsepower outputs'.

'The peerless effort of the 'Royal Scot ' when Lavington bank was climbed ....the engine exerting 1630hp at the drawbar'.

However, the highest power output during the entire trials was by the Duchess (for a very brief period), and then the West Country.

In another book I have, 'Essays in steam' compiled by John Clay from articles written for the Stephenson Locomotive Society house magazine, his own essay on the Royal Scots, before and after rebuilding, includes '[unrebuilt] size for size, their work was not exceeded by contemporary British 4-6-0s or pacifics'. 'It may well be that the average Royal Scot worked more 500T trains than the average King, and, size for size, worked harder than the average Pacific'. It was in the 1948 loco exchanges that the Royal Scots scored their greatest triumph. It was rumored that the LMR authorities were more interested in the RS results rather than the Duchess'. 'It is suggested that continous horse power was just less than a Britannia, (around 2000hp)'. 'The best records of converted RS in sustained high speed haulage of heavy loads has not been surpassed by a King, nor has the highest maximum edhp....' (Note from me-the last statement of equivalent drawbar horsepower is a bit technical, but includes the effect of gravity when climbing gradients). 'they were equal to the best performing 4-6-0s in the world, the partly Chapelonised Est 2.3.0.K'.
'The converted Scots  have a strong claim to be the most thermodynamically efficient 4-6-0s, but the Kings were better riding vehicles'.

Whew, more than enough. If you've kept interest in this fairly technical post, well done!

Martyn

Ok John I give up.  " that three-cylinder 'fliffle-wuffle-flaffle' beat "   Tried all the functions on my dcc controller with my sound fitted 3 cylinder Jubilee, but I just cannot find the 'fliffle-wuffle-flaffle'  function key.    :no:  :)  :)
What a great thread, thank you  :thumbsup:  Alan

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 25


Hello Chums


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-250624114736.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142841)


Part 25!  How did that happen?  When Poppy and I thought it might be a jolly jape to start this threadingham, we envisaged a pawful of postingtons.  And here we are at No. 25 and we're just thinking about boilers.

Thank you so much for your recent contributions, chums.  The 'Converted Royal Scots' were certainly excellent engines, if troubled by rough riding. 46104 Scottish Borderer was the worst.  A Polmadie engine - all this shed's 'Royal Scots' were rough.  46104 was also known to be a poor steamer.

Let's have a think about locomotive boilers - typical ones, mind, none of the fancy stuff.  If you can cast your mind back to Part 24, I commenced it with a picturingham of a roll of lavatory paper in order to give an idea of the diameter of a boiler tube.  Imagine, if you will, the paper has been used and we are left with the cardboard tube.  Before it goes in the green recycling bin, it can be another visual aid - virtual, this time.  Sit it lengthways and we have a passable scale model of a locomotive boiler.

That's right - a tube.  Not made of cardboard but, in the early days of iron (Low Moor iron from near Bradford was considered tip-top) and, from around 1880, of steel.  The LNWR led the way in Britain with steel boilers.  The various sections which made up the boiler were rivetted together - even on the Bulleid 'Pacifics'.  The description of 'welded boiler' often applied to them only is relevent to the firebox.

Imagine making a boiler from sheets of wrought iron.  A couple of sheets of paper will do.  Roll a sheet into a tube, with one end overlapping t'other by, say, half-an-inch and stick the ends together with your choice of glue.  Maybe make another one a tad bigger diameter and stick them together 'telescope' style.  Your 'two-ring' boiler shell.  Now over to Peter Purves with the Blue Peter layout.

A totally tickety-boo boiler shell?  Sadly, no.  Remember Pte Baldrick's Great War poem - 'Boom, boom, boom'.  Well, in mid-Victorian Britain, locomotive boilers staged a grand recital of this poem.  And one of the leading causes was these joints.  What you made earlier is called a lap joint.  A boiler ring with a lap joint was not truly circular and steam pressure tended to distend a boiler made this way into a precisely cylindrical shape.  Once higher steam pressures over 100 psi were used, this became a particular problem.

Each time the boiler pressure varied and, especially, as the boiler was warmed up or cooled down, small stress cracks appeared in the inside of the barrel, along the lap joint.  The cracks rusted, then became a groove and, if the plates were not renewed in time, the boiler split open.  William Kirtley, later Locomotive Superintendent of the London, Chatham & Dover Railway, described the problem, in a paper to the Institution of Mechanical Engineers, in 1866. 

He made it clear lap joints were not suitable for horizontal seems in boiler plates but were suitable for the annular seems that connect one ring to another.  Also, to minimise corrosion, the horizontal joints should be placed above the water line.

As Mr Kirtley had said, the introduction of double-strip butt joints solved the problem, but (sorry) they were adopted slowly.  The last boiler explosion attributable to lap joints and grooving was at Seaton (Cumberland) in 1890. [Furness Railway 0-6-0 ST No. 107 - 27 November.]

If we cut a couple of strips from our sheet of paper, then roll the sheet into a tube, with the ends butting together this time, rather than overlapping, and glue a strip along the join on both the inside and outside of the tube, we've made our own.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-250624113444.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142840)

[A locomotive boiler showing safe riveted joints.]


Boiler diameters of around 4 ft. were commonplace by the Eighteen-Fifties and diameters increased so slowly that, prior to 1896, no locomotive boiler in Britain exceeded 4ft. 6 in.  John McIntosh on the Caledonian caused a right old fuss that year with his famous Dunalastair 4-4-0 with a 4 ft. 9 in. diameter boiler. Diameters soon exceeded 5 ft.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-250624111912.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142838)


As seen in the picturingham, the NER introduced a 5 ft. 6 in. boiler for 0-6-0 locomotives in 1904 which gave locomotive people something to talk about.


The next stir was caused by Mr (later, Sir Nigel) Gresley's 'K3' 2-6-0 of 1920 for the Great Northern with a 6 ft. diameter boiler.  He exceeded this with the 6 ft. 5 in. boiler fitted to his 'A1' 4-6-2 class of 1922 and that diameter became an LNER standard.  It was slightly beaten for British conventional locomotives by the LMS 'Princess Coronation' 4-6-2 of 1937 with a maximum boiler diameter of 6 ft. 5 1/2 in. 

Next time, I'll write some more about boiler-ish matters.  So much to do; the pressure's tremendous!


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

It would not surprise me to find out that as a result of the locomotive exchanges the Kings were trialled with a four row superheater and double chimney with which all of the class were subequently fitted

Regards,

Alex

Quote from: Hailstone on June 25, 2024, 11:52:27 AMIt would not surprise me to find out that as a result of the locomotive exchanges the Kings were trialled with a four row superheater and double chimney with which all of the class were subequently fitted

Regards,

Alex

@Hailstone

Correct, Alex.

CJ Allen in the booklet mentioned in my last post says that there was a separate set of trials for all the (G)WR locos but using Welsh coking coal from Abergorki, which had a higher calorific value than the other coal used in the trials across all the regions for all locos.

But, quote, 'by far the most interesting feature of the additional WR tests ...were those made with King 6022... in which the standard 16 element superheater had been replaced by a 24 element one...changing effectively a steam dryer to a high temperature superheat' and notes that this was the first significant change at Swindon from Churchward's principles.  The new superheater brought coal consumption (and water?) down noticeably. I'm not a student of the GWR, but I think all Kings subsequently had the new superheater, and many had double chimneys.

However, the second book I quoted mentions that Kings never seemed to run as freely as other classes, and many theories were put forward for this; possibly restricted steam pipes between regulator and cylinders. I think it was never really sorted, as they could do the work required of them, but this internal resistance, whatever it was, is thought to have precluded regular really fast running.

The CJA booklet has many insights into the test results, and there's lots more I haven't mentioned, including freight and mixed traffic classes.

(Later- note you say they all later had 24 element superheaters and double chimneys; I had no idea).

HTH

Martyn

 

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 26


Hello Chums

Let's have a quick think about boiler pressure.  It doesn't normally have much of an effect on the external appearance of a locomotive, so probably isn't that relevant for 'N' gauge modellers.  Nevertheless, I think it is worth spending a little time on it.  Let's start with the Rainhill Trials of 1829.  The rules allowed a maximum boiler pressure of 50 pounds per square inch (psi) and the three entrants: Novelty, Rocket and Sans Pareil all used this pressure.

By the mid-1840s, pressures of 100 psi were in use and the celebrated 'Jenny Lind' 2-2-2 locomotives, designed by David Joy and built be EB Wilson & Co, of Leeds from 1847, used a boiler pressure of 120 psi.  These engines were especially successful and much of the credit for this has been attributed to their higher boiler pressure.

Boiler pressures of 120psi or 125 psi were common throughout the 1850s and early 1860s.  By 1865, the LNWR and Midland were using 150 psi for certain express passenger locomotives.  At the end of the century, boiler pressures of 175 or 180 psi were commonplace with 200 psi used on occasion..

Locomotive engineers were aware that higher pressures required heavier construction and, especially, resulted in increased maintenance costs.  Because of this, there was a desire to limit further increases in pressure, and, in some cases, reduce the boiler pressures in use. I'll return to this apparent retreat in a later postington.

An especially good example of a locomotive engineer taking a very cautious approach to boiler pressures is George Hughes, Chief Mechanical Engineer of the Lancashire & Yorkshire, 'Greater' LNWR and LMS.  Mr Hughes is on record as expressing serious reservations regarding high boiler pressures.  His only design for the LMS, the 'Horwich Mogul' 2-6-0 of 1926, is interesting in this regard.  It is usually attributed to 'Hughes/Fowler' as Mr Hughes had retired in 1925 and Sir Henry Fowler added a few of his beloved Midland features to the design.  Not for the better, I think.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-260624165905.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142879)


Mr Hughes wanted a boiler pressure of 180 psi, only 5 psi greater than the Fowler Midland '4F' 0-6-0 of 14 years earlier.  In order to obtain the the required power, 21 in x 26 in outside cylinders¹ were decided upon.  To give sufficient platform clearance (that restricted British loading gauge - and especially on LMS routes in Scotland - again) the cylinders had to be high and sloping.  Just as well I qualified the point in my second sentence with 'normally'.  The picturingham, from a photograph kindly supplied by @Nbodger and taken on his SuperSpiffing Hillsden layout shows a locomotive of this class.

In 1933, Mr (later, Sir William) Stanier introduced his version of a 'Mogul', of the same power classification, to the LMS.  This class had completely horizontal outside cylinders, the only Stanier design to have this feature, of only 18 in. diameter.  This was permitted by a longer stroke, 28 in., and a boiler pressure of 225 psi.  We'll meet this class, of only 40 engines, again.

The next part will concentrate on the engines of the two British locomotive engineers who dared to use higher boiler pressures in the Edwardian era.  Any ideas who they were?


Many thanks to Mike for the photograph.  Is it just me or does the SuperSmelly diesel behind the marvellous 'Mogul' look as if has been crying?

¹ Outside cylinders of over 20 in. diameter were unusual in Britain.  Even the mighty '9F' had 20 in diameter, but I'm getting ahead of myself - this is a subject for a later postington.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-bye

John



   

Quote from: Train Waiting on June 26, 2024, 05:32:33 PMIs it just me or does the SuperSmelly diesel behind the marvellous 'Mogul' look as if has been crying?
 

Maybe sulking, well wouldn't you if you had failed on the overnight Condor two nights earlier then again on the return journey from Manchester Victoria to Leeds. She will soon be visiting Mable's Barrow.

apologies John for for bringing some frivolity to your wonderful thread, will delete if you wish.

Quote from: martyn on June 25, 2024, 01:17:12 PM

Quote from: Hailstone on June 25, 2024, 11:52:27 AMIt would not surprise me to find out that as a result of the locomotive exchanges the Kings were trialled with a four row superheater and double chimney with which all of the class were subequently fitted

Regards,

Alex

@Hailstone

Correct, Alex.

CJ Allen in the booklet mentioned in my last post says that there was a separate set of trials for all the (G)WR locos but using Welsh coking coal from Abergorki, which had a higher calorific value than the other coal used in the trials across all the regions for all locos.

But, quote, 'by far the most interesting feature of the additional WR tests ...were those made with King 6022... in which the standard 16 element superheater had been replaced by a 24 element one...changing effectively a steam dryer to a high temperature superheat' and notes that this was the first significant change at Swindon from Churchward's principles.  The new superheater brought coal consumption (and water?) down noticeably. I'm not a student of the GWR, but I think all Kings subsequently had the new superheater, and many had double chimneys.

However, the second book I quoted mentions that Kings never seemed to run as freely as other classes, and many theories were put forward for this; possibly restricted steam pipes between regulator and cylinders. I think it was never really sorted, as they could do the work required of them, but this internal resistance, whatever it was, is thought to have precluded regular really fast running.

The CJA booklet has many insights into the test results, and there's lots more I haven't mentioned, including freight and mixed traffic classes.

(Later- note you say they all later had 24 element superheaters and double chimneys; I had no idea).

HTH

Martyn

Martyn

as I am abroad and cannot acces my usual bibles I have taken this text from wikipedia

"The class proved to be capable and reliable when using the high-calorific South Wales steam coal, on which the GWR had always relied for its good locomotive performance. However, during the 1948 locomotive exchanges, King Henry VI performed disappointingly using Yorkshire coal, despite demonstrating the 4-6-0 type's unique sure-footedness when climbing out of Kings Cross, where pacific types were apt to slip alarmingly.

As originally built the class had a Swindon superheater with an area of 313 square feet (29.1 m2). However, in 1947 experiments were undertaken with a four-row high-degree superheater in No. 6022 King Edward III. As a result, the four-row superheaters were fitted to the whole class, and modifications were also made to the draughting arrangement, using No. 6001 King Edward VII as a test-bed. From September 1955, double blast-pipes and chimneys were fitted, initially to No. 6015 King Richard III. Following successful testing the whole of the class was subsequently modified and, as a result, their final years in British Railways ownership saw the very best of their performance, particularly on the steep South Devon Banks at Dainton, Rattery, and Hemerdon."

Regards,

Alex

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 27


Hello Chums

In Part 26 we saw that many locomotive engineers of the Edwardian era were reluctant to increase boiler pressures above 200 psi, with most glad to remain in the 150 psi to 180 psi range.  This was due to higher pressure boilers being heavier and, seemingly, much more costly to maintain.

Due to another development we will mention later, some locomotive engineers actually decreased boiler pressures during this decade or so.  A good example is the Glasgow & South Western Railway's '381' class of 17 engines, introduced in 1903, with 180 psi working pressure.  The two engines of the '128' class, of 1911, had a working pressure of only 160 psi.  This demonstrates the reluctance of most locomotive engineers of the time to accept higher boiler pressures.

There were two notable exceptions, one of whom made a lasting contribution to locomotive design and the other was more of a footnote who will receive an honourable mention.

It can be difficult for us now to imagine the impression George Jackson Churchward made on the  locomotive engineering establishment in the first decade of the 20th Century.  He took the best of American practice, added some French features, and created, in the heart of Wiltshire, a series of locomotives which represented a step-change in design and performance.  Not that they were universally popular when introduced - their austere American appearance came as a shock to people used to the 'gilded lilies' that were British locomotives of the time.

The four years from Mr Churchward's appointment as Chief Assistant to William Dean, the GWR's Chief Mechanical Engineer, in 1898, to his own appointment to the post in June 1902, following Mr Dean's retirement, gave Mr Churchward a useful opportunity to experiment.  By the time of his appointment as Chief Mechanical Engineer, he had a good understanding of what he intended to achieve.  An important part of this was concerned with boiler design and construction.

He looked to the USA for the latest developments in boiler design.  Brooks Locomotive Works was an exponent of taper boilers and the Illinois Central Railroad had been using a firebox with with curved rather than flat surfaces, direct staying and a generous space between the inner and outer firebox crowns.  It used a working pressure of 210 psi.  Swindon Drawing office had drawings of this boiler by 1902.¹.

Mr Churchward designed a range of standard, tapered boilers for most new construction, with working pressures of 200 psi for the smaller locomotives and 225 psi for the large engines.  He read his paper, Large Locomotive Boilers to the Institution of Mechanical Engeneers in 1906.  This paper described the important features of his approach to boilers:

Higher working pressures up to 225 psi;
Ample tube spacing;
Effective tube proportions;
Free circulation of water especially in front of the firebox tubeplate;
Ample space for steam inside the boiler above the normal water level - greatly helped by the use of a Belpaire firebox and a taper barrel.

His fellow Chief Mechanical Engineers were not all convinced by this Churchwardian logic and Mr Hughes, whom we met in Part 26 spoke during the discussion about the maintenance difficulties and costs associated with higher boiler pressures.  Mr Hughes was an enthusiast for moderate boiler pressures of not more than 180 psi.

HC King, Swindon Works Manager and without doubt speaking with Mr Churchward's approval, shot this fox by making the point that a boiler properly designed and carefully built to withstand higher pressures would not require increased maintenance, but a boiler designed and built in the traditional way and pressed to higher pressures undoubtably would.

As far as I'm aware, the only other British locomotive engineer to take advantage of higher working pressures at this time was Richard Deeley on the Midland, whose celebrated 'Compound' 4-4-0 locomotives had a working pressure of 220 psi.  Later reduced, under Sir Henry Fowler, to 200 psi.  More of that later.


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-280624103532.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142928)


At the time of the Grouping in 1923, apart from on the Great Western, boiler pressures were in the 180 psi to 200 psi range.  Even the first Gresley 'Pacifics' were only 180 psi.²

Post-Grouping developments came quickly.  Mr Maunsell on the Southern went to 220 psi for his 'Lord Nelson' and 'Schools' classes but otherwise stuck to a 200 psi maximum.  The 'Royal Scot' class, built by the North British Locomotive Company for the LMS used 250 psi. Subsequent locomotive classes, designed by Mr (later, Sir William) Stanier, for the LMS were in the 200 psi to 250 psi range according to the power of the engine, with 225 psi being commonly used.

Mr Churchward's successor on the Great Western, CB Collett, stuck firmly to established practice with the exception of his 'King' class 4-6-0 which had a boiler pressure of 250 psi.

Mr (later, Sir Nigel) Gresley on the LNER took the same approach with a range from 180 psi to 250 psi for the most powerful locomotives.  Interestingly his final design, the two 'V4' engines of 1941 for secondary work also used 250 psi.

There was a slight trend to higher boiler pressures at the end of the Grouping era.  OVS Bulleid used 280 psi for his three Southern 'Pacific' classes and FW Hawksworth also used 280 psi for his 'County' class 4-6-0.  All of these were subsequently reduced to 250 psi.

The BR 'Standard' classes used boiler pressures of 200 psi, 225 psi and 250 psi according to their power classification and it is reasonable to say that this represented the final consensus for British locomotive practice. 


¹ ES Cox, Speaking of Steam, Ian Allan, London, 1971, SBN 7110 0236 3 p45

² Sir Vincent Raven's North Eastern Railway 'Pacifics' were built with a working pressure of 200 psi.


'N' Gauge is Such Fun - even when the pressure's tremendous!

Many thanks for looking and all best wishes.

Pip-pip

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 28


Hello Chums

In Part 27, we mentioned tapered boilers, which Mr Churchward adopted after initially using parallel Belpaire boilers.  A tapered boiler is an obvious feature of a model locomotive and it is worth spending a moment considering the advantages claimed for this type of boiler.

The main one is that the volume of water in the boiler is more concentrated at the firebox end, which is where the heat resulting from combustion is most intense.  As we have seen, Mr Churchward took great care to allow for free circulation of water, especially in front of the firebox tubeplate, and ample space for steam, especially above the firebox.

A taper boiler is lighter at the front which helps with weight distribution as certain heavy components, such as the cylinders, are located at the front of a locomotive.

A taper boiler provides a slightly better forward view for enginemen.

Under braking, when reaching the top of an up gradient or heading down a gradient, the water in the boiler runs towards the front which can risk uncovering the firebox crown.  A taper boiler provides less water capacity at the front and can help to reduce this risk.

A GWR standard tapered boiler was normally  6 in or 7 in less in diameter at the front than the rear.

From being a GWR feature in the Edwardian era, the taper boiler gradually gained general acceptance.  I believe the really important example of that was REL Maunsell's 'K' class 2-6-4T and 'N' class 2-6-0 locomotives for the South Eastern & Chatham Railway, both introduced in 1917.  The designs were prepared in 1914 but construction was delayed by the outbreak of the Great War. The classes used the same type of boiler which tapered from 5 ft. 3 in. at the firebox end to 4 ft 7 1/4 in at the smokebox.

Mr (later, Sir William) Stanier took the GWR-style tapered boiler to the LMS as can be seen in this picturingham of his Class 5 4-6-0:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300624103223.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142998)


Even on the Great Northern and, later, the LNER, where Sir Nigel Gresley had made it clear he did not favour the Belpaire firebox, the boilers on the wide-firebox locomotives had a distinct taper.  I understand Sir Nigel used the term 'coned boiler' to describe these.  For narrow-firebox classes he and his successors preferred the traditional parallel boiler.  This 'B17' 4-6-0 is an example:


(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300624103242.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142999)


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-Bye

John

Thanks again, John.

Popping back a post to boiler pressures, the 280lb/sq in of the Bulleid Pacifics and the GWR 'Counties' was the highest pressure used in the UK for normal locos.

But there were at least two examples of higher pressure locos, albeit one-offs for special testing. There may have been more, I don't know.

The LNER W1 'Baltic' 4.6.4, # 10000 alias the 'Hush Hush' had a pressure of 450 psi as built, and this pressure was used for the high pressure cylinders of the compound design. The boiler was also not the normal 'firetube' (or 'locomotive') boiler, but a water tube one. Let's not go there, Google water tube boiler if you want more details. There were many variations of this type of boiler.....

When rebuilt as a conventional three cylinder loco, the new boiler was 250 psi.

But even exceeding this was the LMS 'Fury' # 6399. Nominally responsible was Fowler, though the boiler was designed by The Superheater Company. The boiler raised steam in three stages, and the first stage used a closed loop recirculating pressure of between 1400-1800 psi. This water heated a second steam source which worked at 900 psi, and this steam was used in the first stage of the compound cylinder arrangement. A third system raised steam at 250 psi for the second stage of the compound arrangement. The loco wasn't successful; a high pressure tube burst on an early trial, killing one of the test staff; and though repaired and run on further tests for four years, it was (nominally) rebuilt as 'Royal Scot' #6107 British Legion. Wiki says that it was economics rather than technical failures which doomed the loco; unlike the original W1, 'Fury' never hauled a revenue-earning train

For further details of these locos, Google has quite a few leads, and the W1 is extensively covered in the RCTS History of the LNER locos, vol. 6C; the latter is now available online.

Martyn

Is that LNER one Dapol or Farish, John? I have a feeling I may own one!

Thank you, John, this is all so interesting. I thought I knew a bit about steam locos, but all I know now is the depth of my ignorance!

Have you thought about editing it into a series for the N Gauge Journal? Or even a small book-ette for the general public to buy? Seems a shame that the fruits of your labours should only be seen by we favoured few.

Thanks also to Martyn and others for their valuable addenda.

Cheers,

Chris

Wot Chris said. :thumbsup:

Quote from: Train Waiting on June 30, 2024, 10:40:42 AMThis 'B17' 4-6-0 is an example:

(https://www.ngaugeforum.co.uk/SMFN/gallery/142/6222-300624103242.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=142999)

Not to be confused with ....

https://en.wikipedia.org/wiki/Boeing_B-17_Flying_Fortress#/media/File:B17_-_Chino_Airshow_2014_(framed).jpg

 :D

Ed

One further thing to remember about boiler pressure.

As the pressure on the water surface increases, so the temperate required to make it boil (and hence produce steam) increases as well.

By the time steam pressure is 225 psi, then it is boiling at 200C/392F (according to a set of tables I found online).

Superheating can take temperatures to 500F or above. The original A1 boilers had superheat steam temperatures of about 575F; trials were arranged to try and make this higher, to about 700F, with a new design of superheater. However, the new design did not have the results hoped for,  with average results only about 30F higher than previously, though a max of about 650F was recorded.

Martyn

Quote from: Bealman on June 30, 2024, 11:59:54 AMIs that LNER one Dapol or Farish, John? I have a feeling I may own one!

It is a Dapol model, George.  I bought it when I ventured into 'N' gauge in 2007.  It is a nice looking model but a shocking runner.  It, and a few others, led me to abandon British 'N' gauge for US-outline, mostly Kato.  What a revelation!

Then, in 2014, I saw a Union Mills advertisement in the Railway Modeller and thought I'd try one.  The 'B12' was, and remains, a very fine model and I returned to British 'N' gauge with some fixed beliefs (hardened prejudices?), subsequently reinforced.

I once tried to give away the 'B17' on our FabulousForum and received no interest.  I'm glad to offer it again if anyone would like it.  At one point I thought about attempting to rebuild it with a Union Mills tender drive but concluded that would be a waste of the Union Mills parts.  One cannot polish a sow's ear.

With all good wishes.

John

(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-020724192800.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143052)

Quote from: Train Waiting on June 30, 2024, 02:32:57 PMOne cannot polish a sow's ear

How very polite, dear boy :)

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 29


Hello Chums


Moving to the inside of the boiler and, although not necessarily appearing to be of direct concern to 'N gauge modellers, there are a couple of matters I'd like to mention as these do influence the appearance of a locomotive.  They might also be of interest.

The first is free gas area through the boiler tubes.  It slowly became clear to locomotive engineers that the ratio of area through the tubes to grate area was important.  It wasn't until the 1920s that Herr Wagner in Germany established that the optimum value was 15%.

The second was tube length.  From around 1895, as the British 4-4-0 developed into the 4-6-0 and, occasionally the 4-4-2, the improvement in performance was often disappointing.  There were often problems with the steaming qualities of some of the new, larger locomotives.  Typically, the new engines had significantly longer boilers than the generally successful 4-4-0s, increasing in length from, say, 11 ft. to 17 ft.  Typical boiler tubes of the period were 1 1/2 in to 1 3/4 in diameter.

Research done by the Pennsylvania railroad at its Altoona test plant, and also by Herr Wagner, established that the optimum tube length to diameter ratio was 100 to 1.

This is, I believe, one of the reasons for the disappointing performance of so many 4-6-0s that were, effectively, extended 4-4-0s.  Put simply, their tubes were not of sufficient diameter for the length of the boiler.  At least part of the solution was the increasing use of tubes of up to 2 1/4 in in British practice.

However, an interesting irony concerns the North Eastern Railway's 'R1' 4-4-0s of 1908.  The 'R' class 4-4-0s of 1899 had been outstanding successful and the 'R1' was an enlargement of the earlier design.  They used a shortened version of the boiler from the 'V' class 'Atlantics' of 1903, 11 ft 3 in between the tubeplates rather than the 4-4-2's 16 ft 3 in.  The larger boiler's 2 in diameter tubes were retained - whilst almost perfectly proportioned in the original use, these were too large in diameter for the shorter boiler and the class was regarded as poor steamers.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-020724112644.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143038)

[The NER 'R' class 4-4-0 - a splendid locomotive with excellent proportions.  Enlargement proved difficult.] 

*

Then along came the 4-6-2, or 'Pacific', even longer than the 4-6-0 or 4-4-2.  The first to run in Britain was Mr Churchward's The Great Bear in 1908.  She appears to have been a shy steamer.  Her boiler was 23 ft in length (I have seen 22 ft 6 in quoted as well but I don't think six inches make much difference here).  I have been unable to find out her tube diameter, but I assume, unless advised otherwise, that it was 2 in, which was used by the GWR on 4-6-0 classes at the time.  According to the formula, this is distinctly undersize and 2 1/4 in diameter might well have been better.

Rather like The Great Bear was, effectively, an elongated 'Star' 4-6-0, Sir Vincent Raven's NER 4-6-2 of 1922 was an enlarged NER 'Atlantic'.  The especially long external appearance of the boiler barrel with three large safety valves at the firebox end resulted in the class nickname being 'Skittle Alleys'.  The boiler barrel was 26 ft long, externally, but the distance between tubeplates was only (only!) 21 ft.  Which takes us on to a feature of some locomotive boilers we have not yet discussed.

The 'combustion chamber' is an extension of the firebox into the boiler barrel, with the firebox tubeplate recessed into the barrel.  The theory is it allows more space for combustion to develop and increases the firebox heating surface.  The basic idea goes back to Mr Dewrance's Condor locomotive of 1845 for the Liverpool & Manchester Railway and was developed by Mr Beattie, Senior, on the London & South Western Railway of the eighteen-fifties.

The GWR had used a combustion chamber in the boilers of its 'Kruger' 4-6-0 and 2-6-0 locomotives of 1899-1903 and these had proved troublesome.  Perhaps that's why Mr Churchward did not use one on The Great Bear.

Sir Vincent Raven's 4-6-2 design had a combustion chamber, as did another 'Pacific' introduced slightly earlier in 1922 - Mr (later, Sir Nigel) Gresley's 'A1'.  The distance between tubeplates on the 'A1' was 19 ft., achieved by using a combustion chamber and setting the smokebox further back than normal, perhaps a contributing factor to the supremely elegant appearance of these engines.

Mr (later, Sir William) Stanier's second design for the LMS was his 'Princess Royal' class of 1933.  These had rather the appearance of an elongated GWR 'King' 4-6-0.  Fortunately, he built two prototypes to see how they would perform - unlike for his later '5XP' 'Jubilee' class, but that's a story for another time.  The Princess Royal and Princess Elizabeth had boilers 20 ft 9 in between the tubeplates.  It became clear that all was not right with the two prototypes and the production series of ten, and the 'Turbomotive', had, amongst other refinements, the distance between tubeplates reduced to 19 ft 3 in by the incorporation of a combustion chamber.

*

I think there is a general point of interest we can see from all of this.

It's that the British 0-6-0 and 4-4-0 locomotives of 1875 - 1900, give or take, were blessed by having intrinsically good proportions.  This was serendipity in action - their designers were unaware of the science behind the good proportions which they had achieved.  Unfortunately, simple enlargement could not be guaranteed to retain these useful proportions and the advantages they conferred.  Time for a digression.

*

Phil Irving, the designer behind much of the Vincent motorcycle, said that the single cylinder machine's many advantages were outweighed by vibration above 350cc.  From the late 1930s, 500cc vertical twin models became popular.  These were easier to start and smoother-running than the 500cc 'Big Singles'.  Then, after the War, partly due to pressure from the US market (you can't beat 'cubes'), the twins' capacities increased to 600cc, 700cc, 750cc and 850cc.  Many riders preferred the original 500cc machines.  Too late, unfortunately, came the British 750cc 'triples' - three in-line cylinders giving perfect balance - Sir Nigel Gresley would have approved!

The point of the digression is to show that enlargement only works so far; after that a redesign is preferrable.  Just like Mr Churchward did in 1902.

*

Back to the proper stuff.  Of the four 'Pacific' classes we discussed ante, I believe the most successful was the GNR/LNER 'A1'.  And it was the only one which was a fresh design, rather than basically an enlargement of a successful smaller locomotive.

I have made the point, several times, that innovation in steam locomotive design moved, to a great extent, away from Britain around the eighteen-sixties.  References, here, to the Pennsylvania Railroad and Herr Wagner reinforce this.  British locomotive engineers, by and large, were aware of these developments, and sometimes took advantage of them, but did not contribute to them to any great extent.

Here is a good example.

In the USA, in 1904, several locomotive builders amalgamated to form what became 'ALCO'.  In 1910, the new firm built an experimental 'Pacific', No. 50000, which it claimed to have 'rationalized proportions of boiler, firebox and cylinders'.  The Pennsylvania Railroad was impressed by No. 50000 and ordered a slightly heavier version of the new design which it tested exhaustively on its Altoona plant.  From this evolved the famous Pennsylvania 'K4' 'Pacific'.  A series of articles was published in Engineering during 1916 and it is understood that these had a profound influence on the design of the 'A1'.

Not only were the Churchward designs greatly influenced by American and French practice, so were the 'Gresley Pacifics'.  Quintessentially British locomotives, but with a great deal of overseas influence.  I don't want to labour the point, but I think it is unhelpful to restrict one's interest to British railways.  A fuller understanding benefits greatly from a wider field of interest.

As for the French influence on LNER locomotives, that's for a later postington.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-020724114036.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143039)

[Sir Nigel Gresley's masterpiece - the 'A4' 4-6-2 of 1935, seen in post-War condition.  This class was the last LNER-designed 'Pacific' to have the ALCO/Altoona/Gresley 'rationalized proportions'.  Later designs varied and we might consider this later.  The excellent 'A4' boiler featured a combustion chamber.]


The 'R' is by Union Mills and the 'A4' is from Minitrix.  Her eight-wheeled tender appears to have been over-demanding of this coarse modeller's dexterity.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-pip

John 

An excellent post again, John. Thank you.

Looking forward to further instalments.

Martyn

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 30


Hello Chums

'Something for Nothing?'

This diversion is so long that it has a postington of its own.  Viewer discretion is advised as it deals with infernal confusion engines and (clothes peg on nose time) SuperSmelly diesels.  It is intended to help make a point about the quest for efficiency but can be avoided happily if desired.

Not much about motor bicycles this time - we'll start with motor cars instead.  Hopefully, we'll get to trains later.  For a while the supercharger (or 'blower') was in vogue.  Driven off the crankshaft, this was a contraption that compressed the inlet charge for induction, resulting in more petrol/air mixture in the cylinder.  This cause a fiercer explosion and a stronger power stroke, allowing your 'Blower Bentley' to thrash the opposition.  A benefit indeed.  Incidentally, WO Bentley was not enthusiastic about supercharging and there was a lot of private development work done.

But the engineering cost (why is there always a cost?) for this benefit was a drain on crankshaft horsepower (hp) to drive the supercharger and, of course, the complexity, and financial cost, of the supercharger.  For racing, providing one had a wealthy sponsor, the latter was liveable with.  As for the former, providing the additional hp obtained exceeded the hp used, the supercharger was a benefit.

Motor bicycle moment; Georg Meir won the 1939 Senior TT with a supercharged BMW flat twin.  Dashed unsporting conduct and jolly bad form.  Post-War, blowers were banned.

Superchargers never really caught on for private motoring as the additional hp obtained was hardly worth the costs for road use.

But what if the benefits of the supercharger could be obtained without a drain on crankshaft hp by making use of the residual power in the hot exhaust gasses that were otherwise going to waste?  The costs would reduce to simply be the cost of the apparatus and the turbocharger arrived on the scene.  Some motor cars have these and the young-at-heart motorists that particularly enjoy them usually refer to them as 'turbos'.

A much, much more beneficial use of turbochargers is for diesel engines in commercial road vehicles. And, of course, the SuperSmelly diesels that run on rails. 


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-030724102811.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143078)

[This English Electric 'Type 21', probably the most successful of the 'Modernisation Plan' diesel classes, has an 8SVT engine developing 1,000 hp.  My late Father-in-Law was an engineman at Inverness and he was particularly impressed by this class, considering them powerful and reliable locomotives.  The model is by Wrenn and is based on Hornby-Dublo tooling.  Someone, not me, has done a magnificent re-numbering job.]


The English Electric designation - '8SVT' - can be explained easily. The number is the number of cylinders, 'S' means supercharged, although it's actually turbocharged, 'V' is the engine type (other types have different letters - 'K' is an example - and 'T' is for traction use.

It was discovered that compressing the inlet charge caused it to heat and a cooler, lower density charge is more efficient, so an 'intercooler' was added to some engines to cool the charge.  This is designated by a 'C' (for cooling) - 8CSVT. A turbocharger and intercooler can make a diesel engine more than half again as powerful than in a normally aspirated state.  This is considered to be well worth the cost associated with the apparatus.

Which takes us to the point.  'Something for nothing' is difficult to obtain in engineering.  Rather, it is all about the cost to benefit ratio.  We'll return to steam in the next part for a first look at an example of the quest for economical increased efficiency.


'N' Gauge is Such Fun - as is Hornby-Dublo and Wrenn!

Many thanks for looking and all best wishes.

Cheerie-B

John

Sorry old chap, but that is an English Electric Type 1, later under TOPS designated Class 20, but its quite rightly still a smelly diesel.

A rarity having to correct your post old chap, but understandable as it's not steamy but smelly

Quote from: Nbodger on July 03, 2024, 11:31:06 AMSorry old chap, but that is an English Electric Type 1, later under TOPS designated Class 20

Often nicknamed 'The Wardrobe' owing to the many doors along its length :D

Two more examples of the English Electric method of designating their engine can be found in the Brush type 2/cl31 and EE type 3/cl37.

I'm pretty sure it was the same basic engine block and cylinders, but the Cl 31 had a 12SVT rated at 1470 hp, and the cl37 a 12CSVT rated at 1750hp.

Because the electrical system of the cl31 could not handle the extra horsepower available in the 12CSVT, the intercooling, being an additional cost and maintenance requirement, was not fitted. The Brush type 2s were initially fitted with Mirrlees engines, (and were, technically, for the pedantic, class 30), but this engine was not found suitable for traction use on BR.

Yet another siding I've taken the thread down...

Martyn

Quote from: Nbodger on July 03, 2024, 11:31:06 AMSorry old chap, but that is an English Electric Type 1, later under TOPS designated Class 20, but its quite rightly still a smelly diesel.

A rarity having to correct your post old chap, but understandable as it's not steamy but smelly

Many thanks for this helpful correction, Mike.  The diesel fumes obviously interfered with the functioning of my brain cell.  Hopefully, it will have recovered before the next steamy affair about feed water heaters, steam domes and a 'helter-skelter lighthouse'.

Thanks again and all best wishes.

John

Thank you for the information on the Class 20. Rather helpful and like other spotters back in the day and indeed Railwaymen referred to them as Type 1s, Choppers or Wardrobes

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 31


Hello Chums

Thank you for putting up with the idiosyncratic Part 30, which was concerned with road vehicles and, oh my giddy aunt, SuperSmelly diesel locomotives.  Hopefully, the reason for the postington will become apparent as we continue the series.

Back, thankfully, to steam locomotives and their boilers.

Once the steam has been generated in the boiler, it needs to be collected somewhere or other in order that it can begin its journey to the cylinders and, eventually, the atmosphere.  From the early days of the steam locomotive, it became obvious that a hot water engine wasn't a good idea and that water carried over with the steam could cause a lot of damage.  We might look into this matter later.  The steam dome was an effective answer.  It involved a hole on the top of the boiler barrel with what looked like an upside-down bucket rivetted over it.  This gave the steam a place to rise well above the water level in the boiler.  An open-ended pipe in the dome took the steam away to do its work.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-040724120517.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143119)


As can be seen from the picturingham, the 'upside-down bucket' looks too functional for British eyes, so many and various were the dome-shaped coverings that designers placed over it for aesthetic reasons.  Some early ones were fluted like something from ancient Athens.  Later on, a simpler dome shape was preferred, sometimes made of brass and highly-polished.  Small boilers allowed these domes to be most impressive features, once described by my late friend Iain Rice as 'mammalian'.  William Dean's locomotives for the Great Western were especially impressive in this regard.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-040724120543.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143120)

['Mammalian, indeed.  A 'Dean Goods' 0-6-0 with the large and shapely dome favoured by Mr Dean.]


However, there was no absolute consensus and whilst we all probably remember the Tri-ang GWR 'Dean Single' with its large shiny dome, we are also likely to be familiar with Patrick Stirling's famous singles for the Great Northern which had domeless boilers.  These could be seen on other engineers' locomotives, especially those of the 'Stirling School' of James Stirling, Matthew Stirling and Hugh Smellie.  In domeless boilers, steam is collected in a perforated pipe set high in the boiler.

Interestingly, Patrick Stirling's earliest engines for the Glasgow & South Western Railway (G&SWR) had domes - he introduced domeless boilers with his '40' class 2-2-2 of 1860.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-040724121044.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143123)

[A 'Stirling Single' but not as we normally think of it.  This is No. 96, one of Mr Stirling's '95' class 2-2-2s of 1854.  Six foot driving wheels. She was withdrawn from capital stock by 1874.  The photograph was taken later in her life, after she had been fitted with an injector and a replacement chimney. I think she looks splendid and the chaps are clearly proud of their charge.  The photograph is from the late JF McEwan's collection.]


Patrick Stirling left the G&SWR in 1866 to join the Great Northern and was succeeded by his younger brother James, who remained in post until 1878 when he went to the South Eastern Railway.  He was succeeded by Hugh Smellie, of the Maryport & Carlisle Railway, who was, in turn succeeded by James Manson, from the Great North of Scotland Railway, in 1890.  Mr Manson's locomotive were fitted with large and shapely steam domes, ending the domeless tradition on the G&SWR.

Later in the 1890s, the orderly transition from Mr Dean to George Jackson Churchward commenced on the Great Western.  Swindon went in the opposite direction to Kilmarnock, as Mr Churchward favoured domeless boilers.  The Great Western continued with boilers of this type, although not exclusively, for the remainder of its existence and these continued to be built well into BR days.  Former Great Western engineers later took the Swindon style of domeless boiler to the South Eastern & Chatham Railway, Southern and LMS.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-040724120613.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143121)

[A typical domeless boiler in the Churchwardian style, in this case a Standard No. 10, fitted to one of Mr Collet's '2251' class 0-6-0s, No. 2284.]


For some of its smaller locomotives, the designs of which were often based on old engines, the GWR continued with the domed boiler.  '74xx' class 0-6-0PT No. 7400, seen in the picturingham, was built in 1936, but the basic design was over a quarter-of-a-century old.  After nationalisation, BR built more of this class, with the final examples appearing in 1950.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-040724134616.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143126)


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 32


Hello Chums

We have already mentioned feed pumps and injectors, both are ways of getting water into the boiler to replace that which becomes steam and ends up in the atmosphere, one way or another.  After its invention by M. Giffard, the injector pretty much replaced the feed pump as a means of putting water in the boiler .  But not completely as, from time to time, locomotive engineers sought to obtain economies by pre-heating the water going into the boiler.  Injectors don't like warm water so feed pumps were normally used with pre-heated water.

FH Trevithick's experiments, from 1901, on the Egyptian State Railways led to an interest in feed water heating as steam locomotive engineers were keen to improve efficiency.  Using the exhaust steam to pre-heat the feedwater for the boiler appeared a good way to get something for nothing.  Except, it wasn't for nothing - the initial cost and continuing maintenance costs of the apparatus had to be taken into account. 

Although some railways around the world persisted with pre-heaters, British engineers eventually abandoned them.  Several serious attempts were made over the years, especially on the LNER with over 50 'B12' 4-6-0 so equipped, culminating in the monumental waste of money that were the 10 Franco-Crosti '9F' 2-10-0s built by BR in 1955.  The costs associated with the apparatus outweighed the benefits in British service.  And, in the case of the '9F's, the footplate conditions were atrocious due to the proximity of the chimney which was placed fairly close to the cab, on the fireman's side.  Unlike earlier efforts with feedwater heaters which were normally on top of the boiler, the Franco-Crosti pre-heater drum was placed below the boiler.

On the LNER, it was found that the feedwater heaters fitted to 'B12' locomotives were susceptible to scaling in hard water areas ('furry kettle' syndrome again).  Those allocated to the former Great North of Scotland area benefitted from generally softer water and were less troublesome.  In any event, the savings were outweighed by the additional maintenance and the feedwater heaters were removed.

I am fortunate that, thanks to a reference given by the late David L Smith¹, I can give an idea of the savings obtained by feedwater heating.  In 1911, James Manson designed two 4-6-0s which were built by the North British Locomotive Co, Nos. 128 and 129.  The locomotives were identical, except that No. 129 was equipped with  Weir feedwater heating apparatus.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-050724093647.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143149)


Both engines performed well in service, No. 129 especially so.  In the autumn of 1911, Mr Manson conducted a comparative trial between the two locomotives.  Both ran 231 miles with a train weighing 242 tons tare.  The results were:
        Coal (Tons/cwt)  Water (gallons)
128    4 12            7,350
129    4 11            7,100  using infectors only
129    4 3              7,200  using feedwater heater only.

As with all steam locomotive tests, the results need to be interpretated with caution, as it has been said the easiest way to improve an engine's performance is to paint the chimney white.  Enginemen, thinking their work is being observed, will tend to perform better.

The improvement in economy was clearly not considered sufficient to pay for the apparatus which was removed in 1919.

I think it is fair to say, rather like the supercharging we discussed in Part 30, the costs associated with feedwater heating outweighed the benefits in day-to-day use.

Therefore, let's assume the locomotive boiler is fed by injectors and the feedwater enters the boiler through a non-return clack valve.  Usual practice became for these to be at the side of the boiler, towards the front, as can be seen in this couple of picturinghams:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-050724094848.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143152)

(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-050724093725.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143150)

[A very neat clack valve arrangement on the 'T9' 4-4-0.  Rather less so on Clan Line.  The clack valves and associated pipework are very obvious features of rebuilt Bulleid 'Pacifics'.  In their original condition this was hidden beneath the air-smoothed casing.]


An alternative is to place the clack valves on top of the boiler. This is called 'top feed' and had been developed in the nineteenth century, firstly in G Spencer's British patent of 1863 and then a similar arrangement was used by Herr Wagner in Germany and M. Chapsal in France.

It had been ignored in Britain until Mr Churchward, on the GWR, incorporated the clack valves beside the safety valves about a quarter of the way down the boiler.  Mr Maunsell copied this arrangement for many of his engines on the South Eastern & Chatham Railway and, later, Southern, making the top feed look rather like a conventional steam dome.  This was referred to by some wags as the 'helter-skelter lighthouse' and can be seen in this 'N' class 2-6-0:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-050724093909.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143151)


The LMS eventually adopted top feed. In Mr (later, Sir William) Stanier's time, this was towards the firebox end of the boiler.  Mr Ivatt later moved the top feed closer to the smokebox - a very distinctive feature of the later 'Black Five' 4-6-0s.  This arrangement injected the cold feedwater into the least hot part of the boiler.

¹ David L Smith, Locomotives of the Glasgow & South Western Railway, David & Charles, Newton Abbot, 1976, ISBN 0 7153 6960 1.  Mr Smith found the results of the trials in the Proceedings of the Institution of Mechanical Engineers, March-April 1913.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Tickety-tonk

John

Many thanks again, John.

There were other, generally patented, feed water systems where the water from the tank was heated before entering the boiler. The LNER, or its predecessors, used a number of designs.

One such was DABEG; here is a description as fitted to an LMS loco;

https://www.facebook.com/story.php/?story_fbid=161463953637888&id=100093228513789&_rdr

Another, and I think similar one (I can't find details) was the Worthington-Simpson design.

I would need to go through each class in my RCTS LNER history books, but I'm sure there may  have been a very simple idea trialled on the GNR, where steam was taken from the exhaust into a heat exchanger below the tender, from which the warmed feed was pumped in; the now condensed waste was discharged below the tender on to the track.

Amongst other LNER classes fitted with ACFI feed water heaters were A1 2576 and A3 2580 and P1 2001 and at least one C7; and Worthington gear to five O1s (Gresley version). I think that some LNER locos had the DABEG type, but without going through each class, I'm not sure which ones.

Eventually, exhaust steam injectors were designed which did much the same job, but without the complication of moving parts, and much simpler to build and maintain.

The ACFI feeds on the B12s were removed from 1937 onward, and either Gresley at that time, or Thompson soon after taking charge, ordered that all such feed water systems were blanked off and then removed.

As has been said, it was found that under average British conditions, the initial cost and then maintenance costs and time meant that economies in coal and water consumption led to the in-service savings being outweighed.

If I find any more examples I'll add them later.

Martyn

Two more feed water heater types I've found;

The Weir system which sems to have functioned much the same as those previously mentioned, with a pump feeding heated water to the boiler; and a name for the 'simple' heater exchanger under the tank, the Willans system. The latter, as well as the heat exchanger, then used a pump ( coincidentally made by Worthington) to pump the water through fire tubes in the boiler, rather like superheater tubes (of which more anon from John) before entering the boiler. One of each of these systems were used (individually) on two locos of GNR/LNER classes Q1 or Q2.

Another problem with these systems was the need for continuous adjustment by the firemen to compensate for the load and hence steam rate of useage. They worked best on long runs where steam demand was reasonably constant, but on short or stop start running, took up a lot of the fireman's time.

Martyn

While I am significantly outside my comfort zone with regards to injectors and feedwater heaters I believe I can say that it was common practice in the US and Canada for feedwater heaters to be used.  There are lots of references in my books to Worthington, Elesco and Coffin type heaters but I would need to do some research to determine their differences and operations (difficult right now as I'm in France!!, and in a couple of weeks I will fulfill a dream and visit le Citi du Train in Mulhouse!)

Anyway, The Elesco type can be seen as a large cylindrical device mounted above the smokebox ahead of the stack

Not sure why it became very common here, especially in later steam locomotive development when they didn't seem to catch on so much in the UK?

That could back up my post that, in British conditions, with relatively short runs and stop/start journeys, that it took up too much time of the fireman, and they didn't get a chance to operate at full potential. Plus the maintenance and cost/benefit analysis (if that was what it was called in the 30s!).

With regards to the systems I've mentioned, these seem to be main differences;

DABEG was driven by valve gear motion.
Weir was a single cylinder single acting steam pump
Worthington was a duplex pump.

Martyn

 

A longish quote from the RCTS green bible concerning ACFI and the LNER P2 #2001 ''male chicken ' (changed by forum) of the North';

'The equipment was a constant source of trouble. To function properly it required the regulator to be open continuously which was not possible on the Aberdeen-Edinburgh main line....One of the engine's regular firemen....could only recall one trip when the ACFI worked perfectly, and that was a [non stop?-not stated} Newcastle to Edinburgh working when...working home from repair at Doncaster'.

End quote.

Martyn

Thank you @grumbeast and @martyn .

Yes indeed, pre-heaters became fairly common in US locomotives.  Martyn has hit the feedwater pump on the head with his replies.  A bit like superheating (which we'll come to when I finally manage to write the postington) only much more so, feedwater heating is only effective when the locomotive is working.

Mr (later, Sir Nigel) Gresley fitted it to the first of his fabulous 'P2' class, which was intended to work between Edinburgh and Aberdeen.  If you are familiar with this route, you will know that it is a curve-fest and has a series of up-and-then-down gradients.  All this requires expert enginemanship and lots 'N' lots of opening and closing of the regulator.

One thing that there is plenty of between Edinburgh and Dundee is coal and, although everyone complained about the price of it in the 'twenties and 'thirties (including the miners in a different context), it was still relatively cheap.  The five other members of the class were not so fitted and it was removed from 'C-o-c-k O' the North'. (To get round the forum censor)

My personal view is that, if any LNER locomotives would benefit from pre-heating, it would have been the 'Pacifics' used on the 'Non-Stop' where the coal saving would have been useful and there were parts of the route which required a continuous steady output from the engine - York to Darlington being the prime example.

In the US, with long distances, many of which required continuous work from the engine, the economies obtained could easily exceed the cost of fitting and maintaining the apparatus.  In parts of the US, especially in the west, maintaining coal and water supplies was hard work and  steam locomotive engineers built some very technically refined locomotives.  Some of the best work done by steam traction in the World was on the AT&SF.

We'll return to the cost/benefit theme in later postingtons.

And, Graham, I hope you have a splendid time in France.

With all good wishes.

John

I'm so sorry, chums.

That 'male chicken' nonsense didn't appear when I 'previewed' my reply.

What a shame that No. 2001's name has been changed by our FabulousForum.

My apologies again.

John

:laughabovepost:

Sorry, I had nowt to do with it!

Why did Christine Keeler move to the North East?

To meet the male chicken of the North  :)

Sorry, back to this magnificent thread. :thumbsup:

Quote from: Train Waiting on July 06, 2024, 09:17:43 AMI'm so sorry, chums.

That 'male chicken' nonsense didn't appear when I 'previewed' my reply.

What a shame that No. 2001's name has been changed by our FabulousForum.

My apologies again.

John

Nor my preview.... :)

Martyn

@Train Waiting Maybe not satisfactory but I've amended the post in the interest of flow (whoever she is)

Ok, I'll amend mine.

Christine went to see the C-o-c-k O the North  ;D

This is a total thread hijack. Let's get back to it!  :thumbsup:

Quote from: grumbeast on July 06, 2024, 06:35:55 AMThere are lots of references in my books to Worthington, Elesco and Coffin type heaters but I would need to do some research to determine their differences and operations (difficult right now as I'm in France!!, and in a couple of weeks I will fulfill a dream and visit le Citi du Train in Mulhouse!)

Make sure you also visit the motor car museum in Mulhouse, especially if you like Bugattis.

The electricity museum is also worth a visit.

OK, so here is a question I have been wanting the answer to for ages, but now the subject has come up this is the obvious time to ask.

What is a clack valve? What does it do and why is it so called?

Thanks again for such a fascinating thread!

Cheers,

Chris

Quote from: Papyrus on July 08, 2024, 04:45:43 PMOK, so here is a question I have been wanting the answer to for ages, but now the subject has come up this is the obvious time to ask.

What is a clack valve? What does it do and why is it so called?

It's a simple non-return valve that is opened by the inlet being at a higher pressure than the outlet, closing when the inlet pressure drops.

The way that a steam injector works produces a water flow at a greater pressure than the steam that created that flow, because the volume has been increased by the addition of the water.
 
This increased pressure opens the clack valve against boiler pressure to let the water into the boiler. When the injector is shut off (or stalls) the pressure drops and the clack valve automatically closes.

They will often have a light spring in them to keep the valve closed when the boiler is cold and not under pressure - less important with top-feed than with bottom or mid-position feeds because a top feed cannot leak water, however a leaky or improperly seated clack valve would prevent the boiler making pressure.

I think it's called a clack valve because of the noise that can be made when it closes.

Thanks Chris! I thought it had to be something like that but it is nice to have it so concisely explained.


Cheers,

Chris

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 33


Hello Chums

We noticed earlier the increase in boiler pressures from 50 psi in Rocket up to 250 psi which became an unofficial standard for the most powerful British steam locomotives.  Of course, if we include the BR 'Standard' classes, it became an official standard as well.  The 'Britannia' 7MT 4-6-2 and '9F' 2-10-0 classes used 250 psi as did the lone '8P' 4-6-2 locomotive Duke of Gloucester, whose true excellence was not discovered until the preservation era.

BR 'Standard' Locomotives in power classes 6, 5 and 4 used 225 psi and those in classes 3 and 2 were pressed to 200 psi.

Although locomotive boilers should be able to cope with a pressure in excess of the design maximum (they are hydraulically tested with pressurised water to about a third more than their working pressure), a safeguard against boilers being subjected to pressures above their limit is required.  This is the safety valves.

The earliest locomotives used a 'steelyard' safety valve in which a weighted lever holds the valve on its seat.  This came from stationary boiler practice but it was found that, on a locomotive, the weights tended to bounce up and down, so the 'Salter's patent balance valves' became normal practice for locomotives.  In these, a spring held the valve on its seat and a pointer on a scale showed the pressure - just like on a spring balance weighing scale.  Unfortunately, these safety valves could be tampered with by the enginemen to increase the boiler pressure and this resulted in some boiler explosions.

In order to prevent tampering, John Ramsbottom of the LNWR invented the famous safety valve named after him in 1856 and most railways adopted it, although spring balance safety valves continued in use for many years.

The disadvantage of Ramsbottom safety valves is that they are quite tall and they were eventually superseded by Ross Pop safety valves, which require less headroom.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-080724154337.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143257)

[Two Ross Pop safety valves, mounted above the firebox, can be seen on this LMS '2MT' 2-6-0.]


The safety valves are normally fitted towards the rear of the boiler, usually over the firebox.  In some earlier locomotives, in an attempt to avoid tampering by enginemen, the safety valves were mounted further forward, usually at the dome.  NER 'Long Boiler'0-6-0 No. 1275, at the National Railway Museum, is a good example.  As is Gladstone or any of the 'Terrier' 0-6-0T locomotives - Mr Stroudley was enamoured of this practice.

Dugald Drummond, and, later, his younger brother Peter, following in the Stroudley tradition, placed the safety valves on top of the dome on their locomotives for the North British, Caledonian, and London & South Western and Highland (mostly)¹, which meant this feature could be seen from Caithness to Cornwall in the Edwardian era.  Dugald Drummond's 4-6-0s for the LSWR and Peter Drummond's locomotives for the Glasgow & South Western had safety valves above the firebox.  This picturingham shows a Dugald Drummond LSWR 'T9' 4-4-0 with the safety valves mounted on the dome²:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-080724154609.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143258)


On the Great Western, in Mr Dean's time, the safety valves were inside a tamper-proof brass casing above the firebox.  Mr Churchward moved the safety valves to the first ring of the boiler, near the firebox, and retained the brass cover, although it grew shorter over time.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-080724155257.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143259)

[The later, shorter, safety valve casing can be seen on this 1927-built '45xx' 2-6-2T, No. 5542.]


Apart from tampering, the main hazards associated with safety valves, assuming they are of sufficient area to allow steam to escape at its maximum rate of generation in the boiler - that's why there is normally more than one, is incorrect assembly by fitters or some defect.

A failure of the safety valves can have catastrophic results.

On 21 April 1909, the boiler of Rhymney Railway 0-6-2T No. 97 exploded.  It was torn off the frames and travelled 45 yards before coming to rest.  Both enginemen and a bystander were killed.  The previous day, a fitter had dismantled and then reassembled the safety valves.  Unfortunately, he did this incorrectly (as simple as putting washers in the wrong place) which  meant the safety valves were held firm on their seats and were unable to open.

Something similar occurred at Buxton to LNWR 0-8-0 No. 134 on 11 November 1921.  This time, the boiler burst spectacularly into pieces, some landing 200 yards away.  Both enginemen died.  This was the last locomotive boiler barrel explosion in Britain (let's make sure it remains so); subsequent boiler explosions were of a different type which we'll come to later.

Due to arrears of maintenance caused by the Great War, No. 134 was overhauled by an engineering works in Glasgow and returned to the Railway in July 1921.  The gunmetal safety valves were mounted in cast iron columns and the valves were placed in a gunmetal bush which also provided the valve seat.  Gunmetal has a coefficient of expansion about twice that of cast iron and the morning of 11 November 1921 was especially cold, which restrained the expansion of the cast iron column.

The fitters in Glasgow made the safety valves tight in their bushes with little play.  All this led to the safety valves sticking and failing to relieve the boiler pressure. Unfortunately, it was assumed the boiler pressure gauge was at fault, although it was changed several times. 

After the explosion, a similar boiler was hydraulically tested to ascertain the maximum pressure it could withstand.  The boiler started to give way at 600 psi.  No wonder No. 134's boiler exploded so dramatically.  Its working pressure was 200 psi.

Just in case anyone is interested, gunmetal is an alloy of copper, tin and zinc.

The cause of this explosion ought not to have been a surprise to anyone as a paper, The Construction of Safety Valves, had been read to the Institution of Mechanical Engineers in 1877.  It warned of the dangers of using metals with different rates of expansion in safety valve assemblies.


¹ On the Highland, the 'Castle' 4-6-0, normally attributed to Mr Drummond but largely a design of his predecessor, David Jones, had the safety valves above the firebox as was Mr Jones' practice.  The three 'Scrap Tank' 0-6-0T shunting engines also had their safety valves over the firebox because they used the boilers from scrapped locomotives.  The first of Mr Drummond's own designs with firebox-mounted safety valves were the 'New Ben' or 'Big Ben' 4-4-0 class of 1908. 

²  Yes, it's No. 301 again - we saw her before in Part 32 - but this time in a different livery.  No trouble is too much to add variety to these postingtons.  Mr Bulleid's 'malachite' no less.  Which permits me to quote this jolly anecdote, from HAV Bulleid's (OVS Bulleid's son) Bulleid of the Southern³.  After he had taken over as Chief Mechanical Engineer of the Southern, in 1937, Mr Bulleid, characteristically, wanted to make the livery more modern and distinctive.  He had a carriage painted in malachite green and brought to Waterloo for the Directors to inspect:-

'[...] when he (Bulleid) overheard one of the anti-malachites remark with emotion that "it ought to be spelled with an 's' instead of a 'c'" he wittily dismissed this as "rather a gutteral remark."'

I daubed the locomotive's safety valves and whistle with a gold-coloured 'Sharpie' marker - I told you I was a coarse modeller.

³ HAV Bulleid, Bulleid of the Southern, Ian Allan, London, 1977 ISBN 0 7110 0689 X.  Pages 93 and 94.

I am much obliged to the Lakeside & Haverthwaite and Gloucestershire Warwickshire Railways for allowing me to potter around their locomotive sheds.

Details of the boiler explosions are from the late CH Hewison's Locomotive Boiler Explosions, David & Charles, Newton Abbot, 1983 ISBN 0-7153-8305-1.  I believe everyone who goes anywhere near steam locomotives or similar machines ought to read this book... every year.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-B

John

Quote from: Train Waiting on July 08, 2024, 09:52:11 PMThe disadvantage of Ramsbottom safety valves is that they are quite tall and they were eventually superseded by Ross Pop safety valves, which require less headroom.

Headroom was not the only advantage of Ross Pop valves, the way they work is better too.

Previous safety valves, like Salters or Ramsbottoms, are lifted purely by the steam pressure working against a spring, so they can weep, or "feather", as they are approaching the set pressure and will only gradually open fully. Likewise they will close gradually.

Pop valves have two pistons and seats, a small one that is lifted by the steam pressure in the boiler and a larger one that is initially closed off by the smaller piston. When the pressure reaches the set value, the small piston opens and the escaping steam now acts upon the large piston. Because the lifting force is now increased by the greater area of the large piston, that overcomes the spring closing force immediately and opens the valve fully.

Because the large piston is held up by the force of the escaping steam, that results in the valve closing later and reducing the boiler pressure to a lower pressure at which the valve opened, thereby avoiding hysteresis and the safety valve constantly opening, closing, opening, closing, etc. Often a pop valve will be designed/set to stay open until the pressure is 10-20 psi lower than the opening pressure.

The change to pop valves also caused a change in firing practices. With the older valves, it was considered a sign of firing prowess to have the safety valve feathering as much as possible. With pop valves, the sign of prowess changed to being able to keep the pressure as high as possible without the safety valves lifting.

This change was partially instigated by requests from stationmasters, due to the noise when a pop valve lifted and to the speed at which a trainshed would fill with steam, but also by the firemen quickly realising that the more they got the safety valve open, the more shovelling they'd have to do to restore the lost pressure.

Thanks again, John.

Not much to add to that. Going back to the ex GER 'Clauds' again, they had four column Ramsbottom valves to make sure excess steam was released. These were later replaced by twin Ross pops. To deal with the then-high pressure of 200psi, the GER Decapod had six Ramsbottom valves, grouped, I think, into a set of four and a set of two, but can't find an immediate reference for that.

Thanks, Chris, for the explanation of the action of Ross pops.

Martyn

I was told by one of the loco maintenance staff at Didcot that the standard pattern safety valve was of the Ramsbotton type, unfortunately I am 1700 miles from my reference library to confirm this. I have a copy of Great Western two cylinder locomotives by E.J (Ernie) Nutty who was one of the Swindon test team that improved the performance of several ex GW locomotves along with S.O Ell which I will look up when I get home. this book was written by Ernie many years ago and is my bible when it comes to Great western locomotives. I was priveliged to meet him when we asked him to inspect 6106 when we were looking to undertake a quick mechanical repair to put it back in service - Ernie's few words disabused the management of the notion and a far more comprehensive repair was undertaken.

Regards,

Alex

This is one hell of a read, I up to about page 8 at the present time, a very enjoyable read. No rush I do not want to finish too soon thanks John.
Chris H.

Quote from: Hailstone on July 09, 2024, 12:07:49 PMI was told by one of the loco maintenance staff at Didcot that the standard pattern safety valve was of the Ramsbotton type, unfortunately I am 1700 miles from my reference library to confirm this. I have a copy of Great Western two cylinder locomotives by E.J (Ernie) Nutty

According to my copy of what I assume is the same book (blue card cover, no publication date but with a preface dated 1977), the safety valves are two independent direct loaded valves fitted into a common casting - which also included the mounting faces for the clack valves if the boiler was top fed.

Each valve has its own spring, unlike the Ramsbottom type where the two valves are linked by a lever at the top and a central spring on that lever to close both valves.

Thank you very much, chums, for your helpful posts on GWR safety valves.

The late Professor Tuplin, who was a close observer of Great Western locomotive practice, stated that the direct-loaded safety valves in their brass casing made 'blowing off' noise less noticeable to people standing near the engine on a station platform or suchlike.

I understand the 'direct-loaded' type of safety valve was a derivative of the early 'steelyard' safety valves where a spring replaced the weight.  Use of these safety valves went back to Timothy Hackworth's time.  Unfortunately, the spring had an adjusting nut which could be tampered with to increase boiler pressure.  'Direct-loaded' safety valves tended to be placed in a brass casing to give some protection from tampering. 

The tamper-proof quality of Ramsbottom safety valves made these a popular choice and their use became widespread, but not universal, from the eighteen-seventies.

*

Quote from: lil chris on July 10, 2024, 09:56:11 AMThis is one hell of a read, I up to about page 8 at the present time, a very enjoyable read. No rush I do not want to finish too soon thanks John.
Chris H.

Many thanks for your kind comments, Chris.  The series has particularly valuable input from expert contributors, to whom I'm especially grateful.

*

Thanks again and all good wishes.

Pip-pip

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 34


Boiler Water Level - 1

Hello Chums

We've already discussed this, so just a brief re-cap.  The inner firebox, normally made of copper in British practice, is secured to the outer firebox, which is part of the steel boiler shell, by lots 'N' lots of stays.  Feedwater is put into the boiler, almost always by an injector, to replace the water converted to steam and ending up in the atmosphere.

Too much water in the boiler is a bad thing as it can get 'carried over' with the steam - this is called 'priming' and can cause all sorts of problems.  So, do not overfill the boiler.  But not enough water in the boiler can be much, much worse.  Here's why.

The top of the inner firebox is called the crown sheet and it receives the maximum amount of heat from the fire.  More than enough to melt the metal from which it's made.  But the water in the boiler acts to cool the crown sheet - 'cool' here is a relative term, of course - and keep the metal below the point where it softens and loses its strength.

But, if the water level in the boiler falls to such an extent that the crown sheet is not covered, it will overheat, the metal will soften and the crown sheet will fail, usually by bulging inwards and pulling off of a stay.  Then the force of the escaping steam will result in a boiler explosion.  Sometimes the inner firebox will split open, in other instances, the softened metal will be pulled off multiple stays and bulge down. 

Stronger construction, with the eventual elimination of lap joints, resulted in the failure of the boiler barrel becoming much less common.  The last instance in Great Britain, as we have already seen, was in 1921 at Buxton.  Boiler explosions from then on were a consequence of inner firebox failure, normally of the crown sheet.  Not all were due to low water level, there were a couple of instances (both Southern Railway tank engines) caused by the stays becoming weakened and breaking, but low water level was the most common cause.

There was a period of almost nineteen years between the Buxton explosion and the next one in Great Britain, which was at Carstairs in 1940 involving 'Princess Coronation' 4-6-2 No. 6224 Princess Alexandria.

There were three boiler explosions involving the US 2-8-0 locomotives which were used during the War - at Honeybourne, Thurston and South Harrow.  We will discuss the cause of these later.

In 1945, there was an explosion at Hinton Admiral involving 'Lord Nelson' 4-6-0 No. 854 Howard of Effingham. 

Princess Alexandria suffered a second boiler explosion at Lamington, which is not that far from Carstairs, in 1948.

Ex GWR 4-6-0 No. 6859 Yiewsley Grange suffered a boiler explosion near Wrexham in 1952.  The last on BR, and fortunately a mild one, occurred in 1962 near Bletchley, involving 'Princess Coronation' 4-6-2 No. 46238 City of Carlisle.

*

From the above it is clear that it is of supreme importance that the enginemen know the water level in the boiler and think about what is going to happen next in their working.

Early locomotive practice, based on what was used on stationary boilers, was to have three try cocks, set vertically on the boiler faceplate, about three inches apart.  The theory was that water should come out of the bottom c ock when it is opened, steam from the top c ock and a sort of water and steam mixture from the middle c ock.  It's can be difficult to obtain an accurate reading as water flashes into steam when it reaches the air. [My apologies for the oddity of spacing, necessary to prevent our FabulousForum making me look foolish.  Again.]

Something better was required and what we think of as a gauge glass was, I believe, first used by John Rastrick in 1829.  Better known for his later work as a civil engineer, he was one of the judges at the Rainhill Trials and a partner in Foster & Rastrick of Stourbridge, builder of the first steam locomotive to work in the USA, the Stourbridge Lion of 1829.

If you think for a moment of many modern electric kettles that are see-through in some way or another, so that the person about to make a pot of 'Yorkshire Tea' can check there is enough water in the kettle, that what Mr Rastrick achieved.  Please allow me to demonstrate with a milk bottle, not that I'd ever put milk in tea:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-210724133825.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143497)

[Easy to see the water level when the container is see-through.  Please note, I added some dye to make the water more prominent - our water here, between the Forth and the Tweed, isn't that colour - honest.]


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-210724133852.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143498)

[Some broon tape helps us to imagine the container, like a locomotive's boiler, is not see-through.  I wonder what the water level is.]


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-210724133915.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143499)

[Mr Rastrik's ingenious way of seeing into the boiler can be demonstrated with the handle of the bottle pretending to be a gauge glass.]


In real life, a gauge glass is a glass tube connected to the boiler by means of shut-off cocks.  It is mounted within a frame and surrounded on three sides by thick glass to offer some protection if the gauge glass bursts, which it can do.  Enginemen carry spares; just in case.  Here's a picturingham:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-210724133938.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143501)

[A single gauge glass on LNWR 2-4-0 No. 790 Hardwicke.  Typical of mid to late Nineteenth Century practice - the locomotive was built in 1892 as a renewal of an earlier engine.]


The gauge glass is so arranged that, when water is in sight at the bottom of the glass, the firebox crown sheet is covered with water.  Any additional margin of safety allowed was a matter for the designer.

By the eighteen-fifties, the gauge glass was becoming the norm on steam locomotives, with a set of try cocks as back-up.  An important improvement, attributed to the German Professor Reuleaux was the inclusion of a ball valve to shut automatically should the gauge glass break.

Later on, duplicate gauge glasses gradually found favour; the Glasgow & South Western used these as early as 1879, but a single gauge glass with two integral try cocks remained GWR practice and was used on GWR-design locomotives built after nationalisation.

Safe operation of a locomotive requires the gauge glasses to be working properly and to be visible.  Enginemen are expected to test the gauge glasses when taking over a locomotive.  Proper functioning requires the steam and water passages into the boiler to be unobstructed and the shut off cocks to be fully open.

The 1940 Lamington explosion was due to a fitter wrongly assembling the components of one gauge glass and the enginemen believing the other gauge glass was out of use.  Unfortunately, the wrongly-assembled gauge glass caused the water in it to rise well above the actual water level in the boiler.

The 1952 Wrexham explosion was due to a fitter over-tightening the glands at the ends of the gauge glass tube which caused the over-compressed rubber packing to distort and obstruct the flow of steam into the glass, resulting in a false high water level.  You will recall that, like all GWR locomotives, Yiewsley Grange had only a single gauge glass.  Western Region instructions required the enginemen to have confirmed the accuracy of the gauge glass by using the two test cocks - unfortunately, neither of them did so.

As an aside, in the Grouping and BR steam era, from 1923 to 1968, this was the only occasion in which a GWR-designed locomotive suffered a boiler explosion, as far as I'm aware.

The 1962 Bletchley explosion was of interest because one gauge glass was so dirty, the fireman could not see the water level.  He relied on the other gauge glass which appeared to be full every time he looked at it, with the water out of sight in the top fitting.  Unfortunately, it was empty.

Unlike in my colourful demonstration above, water is clear, which means that a full gauge glass and an empty one look the same.  However, by 1962, an ingeniously simple safety feature had been used on LNER-designed locomotives for many years:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-210724134029.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143502)

[Seen on the twin gauge glasses on Katie are the diagonal-striped back plates.  In a gauge glass empty of water, the stripes go the same way.  Where they are viewed through water, they appear to go in the opposite direction.  Ingenious or what?  Why did BR not adopt this feature on all of its steam locomotives?  Here's another look at it, on the single gauge glass of the replica Sans Pareil.  You can also see one of the try cocks as well.]


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-210724134055.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143504)


What a brilliant idea.  Incidentally, to the best of my knowledge, no locomotive of LNER- design suffered a boiler explosion in the 1923-1968 period.

The next part will discuss another safety feature designed to protect the crown sheet and will again draw on explosions and a violent blow back to inform our discussion of what can happen when things go wrong.

I gladly acknowledge Locomotive Boiler Explosions by the late CH Hewison and The British Transport Commission's Handbook for Railway Steam Locomotive Enginemen as valued sources of information.  Any errors or omissions are, of course, my own.


'N' Gauge is Such Fun.

Many thanks for looking and all best wishes.

Toodle-pip

John

Wunderful stuff, John. :thumbsup:

Quote from: Bealman on July 22, 2024, 02:22:25 AMWunderful stuff, John. :thumbsup:

Seconded  :thumbsup:


Ed

When I was a trainee fireman at Didcot in the early 1980s I was taught by one of the senior drivers how to read test cocks it is quite simple. if there is water at the level of the test 'male chicken' (changed by forum), when opened, steam will immediately condense on the body of the 'male chicken' (changed by forum). if there is steam behind the 'male chicken' (changed by forum), there will be a small gap between the body of the 'male chicken' (changed by forum) and the condensing steam.(remember that steam is colourless until it condenses) Later as a fireman in my own right and later as a driver, I taught the trainee firemen that followed. If the gauge glass was to blow I taught trainees to open the test cocks and start an injector to put water into the boiler until water was observed at the top test 'male chicken' (changed by forum) and the level maintained like this until the gauge glass had been replaced, which all firemen should be capable of doing.

Regards,

Alex

Quote from: Ed on July 22, 2024, 10:01:59 AM

Quote from: Bealman on July 22, 2024, 02:22:25 AMWunderful stuff, John. :thumbsup:

Seconded  :thumbsup:


Ed

Thirded (is this a correct term?)  :beers:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 35


Boiler Water Level - 2

Hello Chums

Before we start, special thanks to Alex @Hailstone for his expert contribution regarding GWR practice of a single gauge glass and test cocks.

A gauge glass or glasses, with test cocks where appropriate, was the standard British way of advising enginemen of the level of water in the boiler.  BR guidance was to keep the water level in sight in the top half of the glass.

Apart from errors by the enginemen, low boiler water level above the firebox could be caused by cresting a summit, if running chimney first - going over one if tender or bunker first - or braking, as these conditions make water flow away from the firebox.  The firebox crown is at special risk towards the rear of the firebox which is why backward-sloping firebox crowns were introduced; we have already seen Mr Churchward's thoughts on the matter.

Injector (or feed pump) failure is a possibility, there is always a back-up but it's possible both could fail.  An obstruction of the water supply between the water tank/s and the injectors could be a cause.  In pre-Grouping days, it was not uncommon for some enginemen to have a fish in the tender to eat any vegetable matter contaminating the water supply.  But rags and suchlike accidentally dropped in the tank are another matter entirely.

Also, if the engine was struggling for steam, especially on a gradient, the enginemen might be reluctant to put on an injector as the feedwater would cool the boiler and reduce the pressure. 

In later steam days in the USA, some locomotives were fitted with a low water alarm which caused a whistle to sound if the water level was approaching a dangerously low level.

The dreadful boiler explosion, at Hinton West Virginia, which destroyed Chesapeake & Ohio Railroad's 'H-8' 'Allegheny' 2-6-6-6 No. 1642 in 1953 was attributed to crown sheet failure due to low water level. The explosion occurred on straight and level track.  At a point a mile-and-a-half before the explosion, a railwayman saw the locomotive passing.  He believed it to be working on a medium throttle and he heard the low water alarm whistle sounding.

Some time ago, I read the Interstate Commerce Commission's report into the explosion.  It concluded the water level had fallen to seven inches below the firebox crown.  It also noted that the locomotive had a history of repairs requested to the feedwater pump.

Low water alarms are now commonplace in steam plant in Great Britain but, as far as I'm aware, no steam locomotive has been so fitted.

*

The final warning of low water for British enginemen is the fusible plug.  One or more - normally two, sometimes three - of these are screwed into the firebox crown sheet and project about an inch above it into the boiler.  They are made of brass and have a lead core (a bit like graphite in a pencil, seen in cross-section).  Some have a brass button, sort of soldered in place by lead.  Lead has a lower melting point than copper and, if the water level in the boiler drops too low, the fusible plug/s become exposed, the lead melts and allows steam to escape into the firebox.  This, in theory, alerts the enginemen to what is happening.

I think it was Yogi Berra who said, "In theory, theory and practice are always the same.  In practice, they aren't."

With reference to a couple of boiler explosions already mentioned, the enginemen on Yiewsley Grange heard the sound of escaping steam in the firebox and assumed a tube had punctured.  They thought they could get to Wrexham... 

In the Lamington explosion, the enginemen on Princess Alexandria were aware of the sound of escaping steam and stopped at Carstairs, where a foreman and two fitters from the steam shed examined the engine but could not find the source of the leak.  The train then continued on its way...

Fusible plugs are intended as alarms - not as as sometimes stated to allow water into the firebox to extinguish the fire - but steam escaping into a large engine's firebox is difficult to see in the glow of the fire and will be drawn forward towards the tubes by the draught.

There was an incident on the East Lancashire Railway on 25 May 2009 in which the boiler water level on a locomotive hauling a passenger train became low because of trouble with the injectors.  The enginemen eventually got both injectors working, but during this time, one of the fusible plugs melted.  The enginemen did not realise this had occurred and continued going about the work of the day. It was only after the locomotive had gone on shed for disposal that anyone realised what had happened. I regret I have not been able to identify the locomotive concerned.

Fusible plugs require expert fitting and thorough inspection.  Unfortunately, both of these conditions were not met on the Main Line Steam Trust's railway between Loughborough Central and Rothley (now the Great Central Railway) in 1975/76.  The locomotive concerned was a Norwegian 2-6-0, No. 377 King Haakon 7.  In April 1975, while the locomotive was undergoing boiler repairs, a volunteer had reformed the threads on the fusible plugs and crown sheet incorrectly and one of the two fusible plugs was inserted cross-threaded.  The insurance company's boiler inspector certified the boiler without seeing the fusible plugs removed for his examination.

Eventually, on 7 March 1976, the threads on one of the fusible plugs failed and it blew into the firebox.  The resulting 1 5/8 inch hole in the crown sheet allowed steam at 170 psi to erupt into the firebox causing a massive blow back.

*

The following instances are straying slightly from matters of relevance to 'N' gauge modellers but, perhaps, are of interest, as high pressure steam makes no allowance for well-meaning preservationists.

The Gettysburg Railroad in Pennsylvania was the scene of a catastrophic crown sheet failure on 16 June 16, 1995.  Ex Canadian Pacific 4-6-2, No. 1278 was the locomotive involved.  The National Transportation Safety Board's investigation found multiple failures of locomotive maintenance, and training and supervision of personnel, which led to the engine being in an unsafe state.

Kitson-Meyer 0-4-0+0-4-0 Hawk was hauling a passenger train on the Kirklees Light Railway (now the Whistlestop Valley) on 3 July 2011 when water became low in the boiler, melting the fusible plug. The newly-qualified driver did not drop the fire immediately as he ought to have, the locomotive remained coupled to its train and the passengers were not evacuated.  Some time later, a more experienced person arrived on the scene and the fire was dropped.  There was extensive damage to the firebox but, fortunately, the crown sheet did not fail.

There was speculation that a partially-closed valve was the cause of the low water level but a a careful and thorough investigation by the Rail Accident Investigation Branch established that the driver had simply not used the injectors enough to compensate for the water being used.

Finally, I was glad to read that '2MT' 2-6-0 No. 46464 has returned to steam at the Strathspey Railway, 44 years after she suffered firebox damage there after being lit up, by shed staff, with an empty boiler.  They thought they were filling the boiler from an external source but, due to an improper setting of an injector's valves, they were filling the tender.  When the fireman came on duty he noticed the gauge glasses were empty.  By then the damage was done.

Unlike our train sets, steam locomotives, even preserved ones, are not toys.

*

The next part will be short and will consider the most unfortunate experiences with US 2-8-0s on British railways during the War.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

Quote from: Train Waiting on July 24, 2024, 09:12:16 PMApart from errors by the enginemen, low boiler water level above the firebox could be caused by cresting a summit, if running chimney first - going over one if tender or bunker first - or braking, as these conditions make water flow away from the firebox. 

In those circumstances the water level can shift quite alarmingly.
I used to work Bulleids and a WD 2-10-0 "over the Alps" on the Watercress Line.

Coming from Alton it's a 1 in 60 up followed by a (IIRC) 1 in 100 down before stopping at Medstead and Four Marks. With such long boilers, if running smokebox first, we had to ensure that the water level before the top of the hill was right up in the top nut of the gauge glasses because by the time we'd stopped in the station it would be bobbing only just above the bottom nut. We'd still need an injector running because shortly after leaving the station the gradient changed again to 1 in 60 down.
It wasn't as bad running to Alton smokebox first because we were stopping on the uphill gradient so had time to get more water in before cresting the summit.

We also had to be careful running tender first. Generally we'd aim to have the water lower than 1/4 up the gauge glass, otherwise when we'd gone over the summit it'd be well above the top nut and we could risk it priming - water being drawn into the cylinders instead of steam, which doesn't do them any good at all.

Many thanks again, John.

I've amended one of my previous posts about the fusible plug; it wasn't the correct answer!

Looking forward to the next instalment.

Martyn

Quote from: Train Waiting on July 24, 2024, 09:12:16 PMI think it was Yogi Berra who said, "In theory, theory and practice are always the same.  In practice, they aren't."

I hadn't come across that before! I love it and must find a reason to use it.

Great stuff as always, John. Keep it coming.

Cheers,

Chris

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 36


Boiler Water Level - 3: A thread diversion.

Hello Chums

Before I divert the thread, many thanks indeed to Chris @chrism for that fascinating account of the close attention enginemen pay to their boiler water levels going 'Over the Alps'.

The 1940 boiler explosion suffered by No. 6224 Princess Alexandria occurred after cresting Craigenhill Summit and when coasting down towards Carstairs. The enginemen involved did not normally work heavy long distance express trains - this one was 16 coaches - and it was the fireman's first time firing a 'Princess Coronation' 4-6-2.  It appears they were struggling with falling steam pressure climbing the bank and avoided using the injectors.

A combination of Wartime conditions and unfamiliarity with the locomotive type led to this horrid occurrence.

*

A combination of Wartime conditions and unfamiliarity with the locomotive type led to three other horrid occurrences.

These boiler explosions, caused by crown sheet failure, occurred between 17 November 1943 and 30 August 1944 and involved the same class of locomotive.  What on earth was going on?

During the War, the American locomotive builders ALCo, Baldwin and Lima produced over 2,000 'S160' class 2-8-0 engines for US Army service in liberated countries.  As such, they were built to comply with a restricted loading gauge.

Commencing in late 1942, 756 of these locomotives were landed in Britain for eventual use on railway operations in Europe.  398 were loaned to the British railways to augment existing motive power during a time of exceptionally heavy traffic.  All were returned to the US Army by October 1944.  These were good, straightforward and powerful engines which influenced later British design practice - especially Mr Ivatt's '4MT' 2-6-0 class for the LMS.

The explosions were as follows:

Honeybourne (GWR) - 17 November 1943
Thurston (LNER ex GER) 12 January 1944
South Harrow Tunnel (LNER ex GCR) 30 August 1944

The S160 locomotives had one water gauge and three test cocks on the driver's side.  The water gauge was completely different from British practice.  It was called a 'Kinger reflex' gauge and was a vertical case, square in section with three brass sides and the front made of thick glass. The glass had a series of prisms cut into its inner face - this made water appear black and steam silver in colour. 

Unlike a typical British water tube gauge glass, this type was difficult to break in normal service.  Although breakages were unlikely, the shut-off cocks were of the screw valve type, operated remotely from the glass by means of a 2 ft. 6 in. long rod, containing a universal joint, with a handwheel at the end, on the driver's side of the footplate.  The handwheel required a full turn to open or shut the screw valve  Unfortunately, for the water gauge to show a true reading, the valve had to be fully open - even if slightly closed a false high water level would be shown.

The reason for the Honeybourne and Thurston explosions was the steam valve was so stiff (the one involved at Honeybourne had a bent valve spindle) that the driver in each case thought the valve was fully open when it wasn't.

In British practice, providing the everything has been correctly assembled, the simple plug valves, with their restricted range of movement, make it easier to see if they are fully open.  In this picturingham, you can see the valve handles for both gauge glasses on River Irt are vertical and fully open:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-260724163101.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143630)


The third explosion, at South Harrow Tunnel, was the most severe.  It occurred at night, about half-way through the tunnel.  The screw valves were fully open and the water gauge was in good order.  It was assumed that the enginemen misread the glass in the dark - please remember that water appears black in this type of gauge.

This next picturingham, from a photograph taken for the LNER, shows the buckled crown sheet of the locomotive involved in the Thurston explosion.  The view is looking through the firehole:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-260724163828.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143631)


The crown sheet was made of 3/8 in. steel plate and was supported by 238 iron stays.  The engine was fairly new as well.

For a better illustration of a buckled crown sheet, the final picturingham, from a photograph taken for the Southern Railway, shows the inside of the firebox, looking forward to the tubeplate, of 'Lord Nelson' 4-6-0 No. 854, Howard of Effingham, which was involved in the Hinton Admiral explosion on 23 April 1945:

The heat softened the exposed crown sheet to a plastic state until it pulled off the stays - the holes for which are prominent.  Amazingly, the crown sheet has not split.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-260724165416.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143632)


*

This diversion has brought us, I think, almost to the end of the part of this series which looks at boilers and fireboxes.  Just one more postington to go.

Once again, I'm glad to acknowledge the late CE Hewison's Locomotive Boiler Explosions, and the British Transport Commission's Handbook for Railway Steam Locomotive Enginemen as valued sources.  Any errors or omissions are, of course, my own.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerio

John

Thanks once again John, for an educating read.

Wikipedia adds that as well as the awkwardly place valve operating wheels, they had to be opened slowly otherwise the check valves fitted at each end would close and trap water, leading to false readings.

The RCTS green bible mentions that, on the LNER, after the difficulties of operating the gauge were known, on some engines the remotely operated valve was painted red,  opened on shed, and a notice to the effect of 'do not operate this valve' was placed on it.

Martyn

Many thanks, @martyn .

The late Mr Hewison, to whom I hope I have given sufficient acknowledgement, was an LNER shedmaster before joining the Railway Inspectorate.  He states in his book that the four main line railway locomotive superintendents were well aware that the US locomotives' water gauges were unfamiliar to British enginemen and placed a notice 'This valve to be always in the open position' beside the steam c ock.  After the Honeybourne explosion this was changed to 'This valve must be fully open'.  Shedmasters where these locomotives were allocated gave instructions and demonstrations to enginemen about the reflex water gauges.

The tragedy at Thurston was that Ipswich shed, where the crew were based, had instructed enginemen regarding it was the driver's duty to establish that both the water gauge and the test cocks were in working order.  Although many enginemen would have been used to duplicate water gauges and would have found test cocks unfamiliar, the old GE was largely a 'single gauge glass' line, with three tests cocks.  Many ex-GER locomotives at Ipswich had this arrangement, so the accident report stated the the driver ought to have been familiar with the need to check the water level showing in the gauge using the test cocks.

The next time I encounter an 'S160' on a preserved railway, I'll have a look and see if the 'Klinger' gauge has been replaced with a 'conventional' British gauge glass... or two of them.

Thanks again and all good wishes.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 37


Hello Chums

I decided at the start to break this little series into three main sections:

Frames and wheels - the rolling chassis
Boiler and firebox - generating the power
Cylinders and motion - the engine: making the power do something useful.

Of course, these three sections are united in a steam locomotive and breaking them into discrete entities was never going to be easy.

Likewise, this approach prevents a strict chronological analysis of development, the result of which is we have being going back and forward through the years.

Let's summarise some of what we have discussed, as far as the Nineteenth Century is concerned.  I think it's fair to say that, give or take at the margins, we can see four eras, each of 25 years:

1801-1825: The Pioneers. Ending, conveniently, with the opening of the Stockton & Darlington Railway.

1826-1850: The Innovators.  A locomotive of 1850, typically a 2-2-2 passenger engine such as Jenny Lind was far removed from Locomotion No. 1.

1851-1875: The Improvers.  2-4-0s for passenger work were well established but 'Singles' were favoured on some railways and, on the 'Brighton Line', Mr Stroudley later preferred the 0-4-2. Outside-cylinder 4-4-0s appeared in the 'sixties, looking slightly like American locomotives and then the classic British inside-cylinder 4-4-0 arrived at the end of the era - Mr Wheatley's design for the North British in 1871 and Jimmy Stirling's elegant G&SWR '6 Class' 'Bogie' of 1873*.  The 0-6-0 was the norm for goods work.

1876-1900: The Developers.  This was the time when the 4-4-0 and 0-6-0 became bigger and, sometimes, better.  Five axle locomotives appeared - 4-6-0s and 4-4-2s and some railways stretched the 0-6-0 into an 0-8-0.  Encouraged by Mr McIntosh's Dunalastair 4-4-0 of 1896, large-diameter boilers, with higher working pressures that could keep the cylinders well-supplied with steam, began to be used.

Which meant, by the time of Queen Victoria's death in 1901, the typical British locomotive had reached a high state of development.  And, usually, they were jolly good looking. I think it's also fair to say they were coming close to the end of the line as regards power and, importantly, efficiency.

The next era, from 1901-1925 can, I believe, be termed 'The Modernisers'.  The next postington will take us firmly into that era and might, with a bit of luck, help link the section on boilers with that on cylinders and motion.

Let's end with a picturingham:-   


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-280724151357.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143678)


The LNWR 'Precedent' class 2-4-0 was introduced in 1874 and is, I think typical of the type of locomotive that was in general use by 1875 - 2-4-0 for passenger work and 0-6-0 for goods.  I believe it is easy to trace its lineage to the typical Stephenson 2-2-2 and before that, Planet of over forty years earlier. Unfortunately, Robert Stephenson died at age 55 in 1859.  I believe, if he had lived to 70, he would have been well aware that this type of locomotive was a development of his work.  Give her a front bogie and a larger boiler with a side-hinged smokebox door and she could still pass muster twenty-odd years later.

The engine in the picturingham is No. 619 Mabel and she was named after George Stephenson's wife - Robert's mother.  Most agreably, Mabel was exhibited at the Stephenson Centenary in Newcastle upon Tyne in 1881.

* Once later designs of 4-4-0 came to the 'Sou West, the '6 Class' became known as the Aul' Bogies. Anglice: Old Bogies.  The last three of the class, rebuilt by James Manson, lasted until 1930.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 38


Hello Chums

[Warning.  Any physicists who happen to see this postington are advised to hide behind the sofa.  Preferably, a large sofa. In the cause of simplification, liberties, various, will be taken.]

In Part 37 of this mini-series, we saw a picturingham of Mabel, a 2-4-0 locomotive of the LNWR 'Precurser' class introduced in 1874, and I attempted to point out that she was a logical progression of the 'Stephensonian' locomotive going back to Planet of 1830.

I observed that, although boilers got bigger and wheels more plentiful, locomotives to the same basic design concept continued to be built for many years.  Many of these were very good indeed and probably came close to what the power and efficiency that could be obtained from this type of locomotive.

Since the 50 psi pressure required of entrants to the Rainhill Trials in 1829, boiler pressures had risen and pressures of around 175 psi were in widespread use around the start of the 20th Century.  As we have seen, following a thorough examination of overseas practice, Mr Churchward on the GWR was about to adopt 225 psi as a standard for large locomotives.

In order for it to do useful work, the steam which powers a locomotive has to contain as much energy as practicable, bearing in mind the duties it is intended to perform.

*

Now for the fun stuff. Welcome to John's Primary School Science Project.

I enjoyed reading some recent correspondence in a newspaper regarding how tea tastes sub-standard at high altitudes.  The learned correspondents made a point of this being because water boils at a lower temperature than the assumed 100^oC / 212^oF at altitude.  They went on to elaborate that this is due to reduced atmospheric pressure - nominally 14.7 psi at sea level.

Here's an example of my calculation that involves a steam train.  Let's take the train up Yr Wyddfa and walk the final bit to the summit.  Then boil our kettle for a pot of Yorkshire tea.  At 3,560 feet altitude, it will boil at 96.45^oC or 205.6^oF.  As we enjoy (?) our tea we can reflect that the boiling point of water varies with pressure.  The higher the pressure, the higher the boiling point.  As our train makes its way down the mountain, we can confidently assert that the steam in the boiler of the engine is at something over 100^oc / 212^oF.

This is jolly important stuff for locomotive engineers.

From a copy of a nifty table, issued, I believe, by the LMS, I'll give three examples.

Boiler Pressure (psi)  Steam Temperature: (^oc/^oF)

50                  148^oC / 298^oF
175                 192^oC / 377^oF
250                 208^oC / 406^oF

The energy contained in the steam comes from two sources - its pressure and its temperature.  As we have seen, temperature varies with pressure. In the boiler, where steam and water are contained in the same vessel, the maximum pressure and, therefore, the maximum temperature is controlled by the safety valves. Steam in this situation is called 'saturated steam' or, more colloquially, 'wet steam'.

As we have already seen, higher pressures require more careful boiler construction, potentially more weight and increased maintenance.  We have noted that the maximum boiler pressure used in normal railway service in Great Britain settled at 250psi.

All of which leads to the conclusion that the maximum temperature of saturated steam in the context of British railways would be 208^oC / 406^oF.  A problem with saturated steam at (relatively) low temperatures is, whenever it leaves the boiler it suffers from heat loss, leading to potential condensation (returning to liquid state) in the cylinders.

To obtain maximum power, it is important to minimise heat loss.  The latest developments in steam locomotives make great use of lagging.  Interestingly, it is believed what made Robert Stephenson decide on inside cylinders for Planet (with the consequent complexity of a crank axle) was Richard Trevithick telling him about the extraordinary increase in efficiency he had obtained in an old beam engine by fitting a jacket around the cylinder to minimise loss of heat by radiation.  In Planet, Robert Stephenson enclosed the cylinders with the smokebox.  We'll discuss another advantage of inside cylinders later, in the next section.

*

Hopefully, my science project gives an idea of the situation facing locomotive engineers.  What was needed was wizard wheeze to increase the temperature of the steam other than by increasing boiler pressures to a point beyond that achievable by the technology, materials and techniques of the time.

In other words, they were looking for ways to 'superheat' the steam.  Superheated steam (quick reversion to my science project) can be defined as steam at a temperature higher than its vaporisation point at a given pressure.

As far as I can establish, James McConnell on the Southern Division of the LNWR was first to experiment with superheating, in 1852, but the first really successful application in Great Britain was in JAF Aspinall's twentieth 'Atlantic' 4-4-2 for the Lancashire & Yorkshire Railway, No. 737 of 1899. 

Mr Aspinall's superheater was a  3 ft. 6 in. long drum fitting inside the smokebox.  The drum had a series of tubes and the hot gasses from the fire, having passed through the boiler tubes, then passed through the drum's tubes, further heating the steam inside. It was accepted that, being located at the coolest end of the flow of hot gasses, the additional heat imparted to the steam was modest, around 35^oC / 95^oF above the steam temperature generated by the boiler which was pressed to 180 psi.  The term for this type of device is a 'smokebox superheater'. Five similar locomotives were fitted with these in 1902.

Twelve years afterwards, Mr Aspinall (later, Sir John) mentioned that these smokebox superheaters were more like steam driers than true superheaters.  In fact the Drummond brothers, Dugald and Peter, on the L&SWR and G&SWR respectively, put a couple of short cast steel boxes in the smokeboxes of some of their later designs.  The steam was led through these boxes which were heated by the hot gasses in the smokebox.  I don't think it was worth the bother as the increase in steam temperature was in the region of 6.5^oC / 20^oF.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-290724170504.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143701)

[G&SWR 0-6-0 No. 300 of Peter Drummond's '279' class of 1913.  The heaviest British 0-6-0 until the introduction of the LNER 'J38' class in 1926.  Festooned with Drummond gadgetry, including a steam drier in the smokebox, these were thoroughly disappointing engines.  Coal consumption was half as much again as the locomotives they replaced and an official G&SWR report described their oil consumption as enormous.  The enginemen petitioned for a bonus for working on these engines.  They were successful.] 


A much more elaborate smokebox superheater, the Phoenix, was marketed in the 1908-1914 period by the New Superheater Company.  The Furness and Hull & Barnsley both used it on several locomotives and other companies tried it on one.  Although reasonably effective, one fitted to a LB&SCR 'B4' 4-4-0 allegedly raised the steam temperature from 193^oC / 380F to 277^oC / 530^oF, it made tube cleaning and maintenance difficult.

The smokebox superheater or steam drier was an evolutionary dead end.  The way forward lay in a foreign invention by, titter ye not, 'Hot Steam Willy', as we will, hopefully, see in the next part.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

PS Please do let me know if you see any dodgy figures.  I never trust my calculations.

This ex-physics teacher awards you 10/10, and you get an early lunch mark too  ;)

A wonderful explanation, John. You've explained a complicated concept very clearly.

As ever, looking forward to the next part.

Martyn

Quote from: Bealman on July 30, 2024, 02:45:16 AMThis ex-physics teacher awards you 10/10, and you get an early lunch mark too  ;)

Thank you, George.

Blimey! 10/10.  I'll spend the rest of the day attempting to convert that to centigrade.

By the way, is it possible to be an 'ex-physics teacher'?  I should have thought that the teaching continues to be done, but in a different environment.

Sadly, I'm not brave enough to subject my theory to rigorous scientific testing by painting the water in Port Poppy harbour on the SuperSilly Train Set Layout blue.

I'd better get back to writing the next postington about superheated steam.  This will involve lots 'N' lots of exciting+++ ^oF to ^oC calculations.  One takes something off and then divides by something else.

*

Quote from: martyn on July 30, 2024, 08:17:43 AMA wonderful explanation, John. You've explained a complicated concept very clearly.

As ever, looking forward to the next part.

Martyn

Many thanks, Martyn.  The next bit gets even more complicated which caused my brain cell to superheat, so I enlisted some expert help.

*

Thanks again, chums, and all good wishes.

John

I used to carry that conversion formula around in me head. Yeah, I remember you have to divide by something. Unfortunately, these days, it's gone out of the window, like Monty Python's biny little turds.  ;)

It's is stuck in my head, C to F is: x 9 / 5 + 32 (times nine, divide by 5 and add 32).

Sad ain't I  :laugh:



Ed

No, not at all. Jogged me memory! Yep, I knew 9 was in there somewhere.

Anyway, back to John's brilliant thread. :thumbsup:

If you can never remember whether to add or subtract 32, or to do it at the start or the end, try this version:

C to F: add 40, times 9, divide 5, subtract 40.
F to C: add 40, times 5, divide 9, subtract 40.

All this talk of superheating reminds me of the thermodynamics I partly understood at university. IIRC an idealised steam engine is a Carnot cycle, whose maximum efficiency is (T2 - T1) / T2, where T2 and T1 are the high and low temperatures in Kelvin. Adding superheating for the pragmatic reason of avoiding condensation in the cylinders increases T2 and so makes the engine potentially more efficient.

Many years ago my parents were on holiday an France and my dad noticed the town square was called "place Carnot". He went into the tourist information office to ask if it was named after the engineer. They didn't know off hand, but had a national biographical dictionary in which they looked up all the Carnots to find one with a local connection. It wasn't the engineer, to my dad's disappointment.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 39


Hello Chums

How many times do we read something a bit like, 'The GWR stuck to low degree superheating until Mr Hawksworth started fitting three row and four row superheaters'?

Which sort of begs the question, 'What, in the name of ten types of coupling rod, is low degree superheating or three row and four row superheaters?'

Let's see if we can find out.

But first, full disclosure.  I got stuck drafting this postington.  The more I tried to unstick myself, the worse it got.  I simply could not get what I was attempting to say clear enough in my head.  I sought assistance from Friend of Poppingham @Hailstone, and Alex and his friend Ted conferred.  Alex then sent me a message of resounding clarity and followed up with a telephone call.  I am hugely indebted to these two expert enginemen for their kind help.

However, and importantly, any errors or omissions in what follows are mine and mine alone.

***

Right-oh - back to 'Hot Steam Willy'.

You might recall my contention (controversial?) that with one or two exceptions, Great Britain lost its early lead in steam locomotive development around the mid-eighteen-sixties.  What, to me, is one of the most important improvements to the basic Stephensonian locomotive was the practical realisation of an old idea.  And it happened East of Lowestoft.  In Prussia.

After some years of experimentation, initially with smokebox superheaters (please see Part 38 to find out about these), Wilhelm Schmidt designed a practical fire tube superheater.  The first was fitted to a Prussian State Railways' (KPEV) 'G8' 0-8-0 in 1902.  KPEV went in for standardisation and quantity production in a big way and several thousand more of these superheated locomotives were built.

This was transformative.

I propose we start off by discussing what a fire tube superheater is and then end this section on boilers and fireboxes with a brief outline of their adoption in Great Britain.

Dr Schmidt's insight was that, rather than relying on some contraption in the smokebox to attempt to superheat the steam, using the hot gasses from the fire, which had travelled through the boiler tubes, at their coolest, it would be better to pass the steam through the boiler tubes themselves.  Or, to be exact, some of them.

To do this he installed a vessel, consisting of two parts, in the smokebox, at the top of the tubeplate.  This is called the 'superheater header'.  Steam from the boiler passes though the regulator valve, normally located in the steam dome, and flows to one side of the superheater header.  From there it passes through the 'superheater elements' which are located inside the 'flue tubes'.  The flue tubes are like large diameter boiler tubes, typically 5 in. - 5 1/2 in. diameter, rather than the 2 in. or so of 'normal' boiler tubes.

The superheater elements are normally about 1 3/8 in. outside diameter steel tubes and make four passes through a flue tube - with two 'u-bends' at the firebox end and one at the smokebox end, returning to the separate side of the superheater header where the now-superheated steam is available to do its work.

Incidentally, the 'u-bends' at the firebox end of the flue tubes are a short distance before the tubeplate, to prevent them from coming into contact with flames from the fire.

Bearing in mind that a picture is worth a thousand words - especially my words - time for a picturingham:


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-300724131627.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143732)


Here, thanks to the patience and courtesy of the wonderful people at the Lakeside & Haverthwaite Railway who, amazingly, don't take exception to my examining their locomotives' innards, we can see the smokebox tubeplate, the superheater header, the boiler tubes, flue tubes and the superheater elements. Even with my course photography, you might just be able to see some of the superheater elements' smokebox end 'u-bends'  By the way, my head was inside the smokebox and the steampipes from the superheater header to the cylinders have been removed.  As have some other things that don't concern us at present.

The boiler is from Fairburn 2-6-4T No. 42085.

Compared to a non-superheated locomotive, a superheated one has fewer 'normal' boiler tubes.  As an example, a BR 'Britannia' 4-6-2 has only 136 boiler tubes but has 40 flue tubes.

The Fairburn tank engine, with a smaller diameter boiler, has 21 flue tubes - I haven't counted the boiler tubes.

Now for that ''x' row superheater' term that we often encounter.  As you can see from the picturingham, the flue tubes are arranged in rows - in this example, three rows of seven flue tubes.  That's a 21 element, three row superheater.

A 'Britannia' has five rows of eight flue tubes, giving it a 40 element, five row superheater.

Put simply, the more superheater elements there are, the higher the steam temperature that will be achieved.

Dr Schmidt recommended that the area though the superheater flues and the boiler tubes should be the same - a 50/50 ratio.  He advocated a target steam temperature of 650^oF / 343^oC, hence his becoming known as 'Hot Steam Willy'.  Please remember that a typical non-superheated locomotive of the time, with a boiler pressure of 175 psi, would have a steam temperature of 377^oF / 192^oC.

Here, possibly of interest, are some superheated steam temperatures recorded at the BR Rugby Test Plant, with the engines working a full power.  The figures in brackets are the number of superheater elements:

LNER 'B1' 4-6-0 (24) - 650^oF / 343^oC
LMS '5MT' 4-6-0 (28) - 680^oF / 360^oC
SR 'MN'  4-6-2 (40) -  700^oF / 371^oC
LMS '8P'  4-6-2 (40) - 710^oF / 376^oC
BR '7MT'  4-6-2 (40) - 730^oF / 387^oC
LNER 'V2' 2-6-2 (43) - 740^oF / 393^oC

Hopefully, Dr Schmidt would have been impressed.

Happily, superheated steam increases in volume compared with saturated steam.  The increase is, on average, in the order of 30 per cent.  This means the boiler has to supply less steam to the cylinders with a resultant saving in coal and water consumption.  Magic!

On a practical level, figures prepared by several railway companies that were adopting superheating in 1906-1913 period showed superheated locomotives achieved an average economy of around 17 per cent based on coal consumption per train mile.  Superheated locomotives also used less water and had an improved haulage capacity.

All in all - a huge step forward.  More to follow.

Thanks, again, to Alex and Ted :beers: .


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-Bye

John

Excellent read and easily understood even by a Bodger.

I worked frequently with a colleague who if he was in a meeting and didn't comprehend the discussion he would ask would you please repeat that but in Janet and John language. Interestingly I am having lunch with him on Thursday.

Quote from: Train Waiting on July 30, 2024, 07:21:59 PMThe superheater elements are normally about 1 3/8 in. outside diameter steel tubes and make three passes through a flue tube - with two 'u-bends' at the firebox end and one at the smokebox end, returning to the separate side of the superheater header where the now-superheated steam is available to do its work.

Actually, and I suspect this is only a typo, it's four passes through the flue tube - back, forward, back and forward again.

QuotePut simply, the more superheater elements there are, the higher the steam temperature that will be achieved.

I don't completely agree with this statement. Each element only has four passes through the flue so it cannot absorb more heat if it has 39 "partners" than if it only has 20.

The main advantage of a greater number of elements is that they can deliver superheated steam at a greater rate than a smaller number can.
In most cases, once the designers had mastered it, the number of elements was chosen to give the required steam flow for the number and size of the cylinders and the speed at which the loco was intended to run - i.e. to ensure that the required volume of steam was available. It's no good delivering steam 100-200 degrees hotter if it can't get to the cylinders quickly enough.

There would be a increase in temperature if the speed at which the steam passed through the elements was reduced by increasing the number of elements (e.g. putting 40 elements in instead of only 20 in the same loco and boiler) but that would have been a secondary consideration, IMO.

Many thanks for this helpful contribution, Chris.

Yes, there was a typo - thank you so much for mentioning it - and is now corrected.  I proof read the post numerous times and still missed that glaring error.  Thank you.

With regard to your second point, I wonder if higher superheat temperatures and, therefore, drier steam was achieved by increasing the number of superheater elements which could then deal more effectively with high volume throughput of steam.

The temperatures I quoted were measured at the time - I think the Rugby Test Plant examples I included are interesting as, even allowing for different designs and covering power classes 5-8, the steam temperature achieved at maximum power correlates to the number of elements from the 'B1' with 24 to the 'V2' with 43.

I'm sorry for being so shockingly untechnical, but might the answer to this lie in the easier 'throughput' of steam with more superheater elements?

The next part will look at the introduction of fire tube superheaters in Great Britain.  I have included some points from a three-way discussion which occurred after Henry Fowler read a paper on superheating to the Institution of Civil Engineers in 1913.

The BTC's Handbook for Steam Locomotive Enginemen of 1957 states on page 36:

'The temperature of superheated steam at working pressure ranges from about 600^oF to 750^oF depending on the design of the superheater and the way in which the locomotive is being worked.'

The Rugby data has steam temperatures taken at 25%, 50%, 75% and full power.  All the locomotives show the degree of superheat being achieved rising as the power output increases. In the 'B1's' case, with 24 elements, from 520^oF at 25% to 650^oF at full power.

I hope we get further helpful contributions to this fascinating discussion.

Thanks again, Chris.

With all good wishes.

John

Quote from: Train Waiting on July 31, 2024, 09:30:08 AMWith regard to your second point, I wonder if higher superheat temperatures and, therefore, drier steam was achieved by increasing the number of superheater elements which could then deal more effectively with high volume throughput of steam.

Yes, that's right.

The faster that the steam is passing through a single element, the less superheating it will gain. Therefore, for a desired rate of throughput, increasing the number of elements means that the steam is going through each one slower and therefore getting more superheat.
Also, more elements will reduce the risk of the power output being "throttled" if the steam can't flow through the superheater fast enough to keep up with the demand from the cylinders.

As with everything, it was a fine balancing act to design a boiler to have sufficient main heating surface area and sufficient superheating surface area for the intended work. Too many superheating flues could result in too few small boiler tubes and, hence, a reduced overall heating surface area so the boiler wouldn't produce enough steam in the first place.

That's why the designers didn't just make all the boiler tubes flue tubes and run superheating elements through the lot.  A superheating flue has a smaller surface area than the four (possibly five) small tubes that it replaces, plus it loses some heat to the steam in the element when the loco's running. Therefore the overall heat and surface area available for making the saturated steam would be too small.

Regarding superheat temperatures, my earlier post on the 'E special' superheater tried on the A1s may have some relevance. The larger heating area did not correspond to the expected gain in superheat temperature.

Also, without going through all my 'green bibles', I'm pretty sure that it was realised that the LNER boiler designs were approaching the theoretical maximum temperatures. Again, I think that shortening one design's superheater loops actually resulted in higher temperatures-I'm not sure.

And also, the later LNER boiler designs were critised because of the ratio of small to superheater tubes and also firebox size; it is stated in one of the books that too much 'wet steam' was being generated and that the superheater was consequently working below optimum.

I think, and will check later.

And regarding overall design, the main steam pipes, regulator, and steam collector , as well as the superheater header and tubes had to be capable of handling the quantity of steam being generated and used; the A4s had large diameter steam pipes, a reverse bend in the A1/A3 steam pipes/cylinder block eliminated, and the pipe joints machined internally to avoid restrictions and obstructions.


Since reading this wonderful thread, I've also had an 'I wonder?' As the superheater raised temperatures and hence increased steam volume, did the increased heat energy mean that more energy was available to be changed to mechanical energy by the cylinders? I haven't a clue.



Martyn

Hi John

It was my understainding the GWR preferred a low degree of superheat due to limitations with the cylinder lubrication, the oils available at the time carbonised at higher superheat temperatures.
It was not until the introduction of synthetic lubricants that higher superheat temperatures were attainable.

Alan

Quote from: martyn on July 31, 2024, 12:01:17 PMSince reading this wonderful thread, I've also had an 'I wonder?' As the superheater raised temperatures and hence increased steam volume, did the increased heat energy mean that more energy was available to be changed to mechanical energy by the cylinders? I haven't a clue.

Happy to be corrected but I would have said not - or not much.

A cylinder can only ingest a fixed volume of steam and, if that's superheated, it will be more expanded and contain fewer molecules than if it's saturated steam. There will be a pressure increase due to the higher temperature but whether or not that offsets the reduced mass and does cause greater power I'm not sure.

The principle advantages of superheating are a reduced tendency for the steam to condense back to water in the steam passages and cylinders and reduced consumption of water and coal.

There are disadvantages too, mainly the cost of fitting and maintenance but, in general, the advantages outweighed the disadvantages - for higher speed working at least. It wasn't found of much use for shunting locos nor for slow traffic.

For example, the North Eastern Railway fitted superheaters to some of its Class P mineral locomotives but later began to remove them.

And I would say, yes ...  :hmmm:

On the above mentioned Prussian G8 the superheater enabled the increase of the cylinders compared to their "wet steam" predecessors, the G7.1.
On the G7.1 the cylinders had a bore and stroke of 520x600 mm which was increased to 550x660 for the first few G8s. Within three years the G8 cylinder diameter was enlarged three times to 575, 590 and 600 mm, enabled by the improvements in superheater technology between 1902 and 1906.

Quote from: Hiawatha on July 31, 2024, 03:33:02 PMAnd I would say, yes ...  :hmmm:

On the above mentioned Prussian G8 the superheater enabled the increase of the cylinders compared to their "wet steam" predecessors, the G7.1.
On the G7.1 the cylinders had a bore and stroke of 520x600 mm which was increased to 550x660 for the first few G8s. Within three years the G8 cylinder diameter was enlarged three times to 575, 590 and 600 mm, enabled by the improvements in superheater technology between 1902 and 1906.

But could that not be that the superheater improvements enabled a greater steam delivery rate to the cylinders, allowing larger cylinder to be fitted and, therefore, an increased power output?

According to Wikipedia, as well as the cylinder diameter increase, they also increased the grate area, evaporative surface area and superheater surface area, all of which would help to create more steam to suit the larger cylinders.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 40


Hello Chums

First things first.  Thank you very much, chums, for all these helpful contributions to the discussion.

*

British locomotive engineers, or, at least, some of them, took an interest in developments overseas and Dr Schmidt's invention attracted attention.  As far as I'm aware, first from the distinctly scientifically-inclined Locomotive Superintendent of the Midland Railway, Richard Deeley, who requested his Board's approval to build forty 4-4-0s fitted with Schmidt superheaters.  This was in April 1904, barely two years after the introduction of the first KPEV 'G8' 0-8-0.  The cost of the superheater apparatus would be about £250 per engine, with an additional royalty fee of £30 for each superheater.

Perhaps Mr Deeley's understanding of the significance of Dr Schmidt's invention made him too enthusiastic and he should have requested permission to equip a couple of engines in the first instance, as a trial.  But the Midland's Board - Successful Northern Men, I like to think - based in the centre of the Railway Universe - Derby - took exception to the cost; especially the royalty fee.

I think it's important to give Mr Deeley acknowledgement for trying.  Credit for succeeding goes to a practical engineer who looked like the member of the Devonian Squirearchy he was.  And to his Board of distinctly aristocratic composition.

In May 1906, Great Western Railway 'Saint' 4-6-0 No. 2901, later named Lady Superior, was the first British locomotive with a fire tube superheater.  And a true Lady Superior she was.

A few months later, that excellent engineer and Chief Mechanical Engineer of the Lancashire & Yorkshire Railway, George Hughes, fitted Schmidt superheaters to a couple of 0-6-0 engines.

What really attracted everyone's attention was the exploits of two LB&SCR 'I3' 4-4-2T engines.  Douglas Earle Marsh, the company's Locomotive Superintendent, had travelled extensively in Europe, observing the latest developments and, by 1907, was considering the use of superheating.  With a lot of assistance from the Schmidt Superheater Company, including Dr Schmidt himself, No. 21 appeared in 1908.  After some further design tinkering, she was followed by Nos 22-26 and then No. 77-81.  At the insistence of the company's Board some of the class were built without superheaters.  In service, the superheated examples were better, much better.

Which brings us to the newly-introduced through train working of the 'Sunny South Express' in November 1909.  LB&SCR and LNWR locomotives worked this train turn about between Rugby and Brighton - a round trip of 264 miles.  Ninety miles between Rugby and East Croydon were run non-stop - no opportunity for the tank engine to take water.

The 'I3' engines used, Nos. 23 and 26, achieved remarkable coal and water consumption figures - 27.4 lbs and 22.4 gals per mile.

The LNWR used one of George Whale's 'Precursor' 4-4-0s, No. 7 Titan, which consumed 41.2 lbs and 36.6 gals per mile.  The 'Precursor' was worked hard and was reputed to have arrived in Brighton on occasions with her smokebox glowing red.

These events caused a stir.  One result of which was the LNWR's new 'George the Fifth' 4-4-0s, designed by Mr Whale's successor, Mr Bowen Cooke, were fitted with Schmidt superheaters.

Other railways were fitting Schmidt superheaters as well and, in some cases, this led to what we might think of as 'backwards progress'.  We have already seen Mr Churchward advocating higher boiler pressures and stating that, if cleverly designed, carefully made and diligently maintained, these did not incur the fearsome maintenance costs many engineers assumed.

Contrariwise, we also saw George Hughes of the L&Y advocating lower boiler pressures and how this resulted in the LMS Hughes/Fowler 2-6-0s having sloping outside cylinders due to their large diameter.

Some other engineers, good engineers at that, tended more to Mr Hughes' view.  The first Scottish engine with a Schmidt superheater was JF McIntosh's Caledonian Railway 4-4-0,  No. 139 of July 1910, a development of the 'Dunalastair IV' class.  Mr McIntosh took advantage of the superheater to lower her boiler pressure from the 180 psi of the the 'Dunalastair IV' class to 165 psi. Nevertheless, she was an outstanding performer and was used on the prestigious trains.  She showed a coal saving of 16 per cent per ton mile.

Well advanced in design when No. 139 appeared, James Manson's two G&SWR superheated 4-6-0s, Nos. 128 and 129, entered service in 1911.  These were equipped with 21 element Schmidt superheaters which, on test, gave steam temperatures ranging from 600^oF / 315^oC to 650^oF / 343^oC.  These two engines gave sparkling performances; it was calculated they could develop 900 drawbar horsepower (dbhp).  Their predecessors, the '381' class 4-6-0s, built between 1903 and 1911, developed a maximum of 750 dbhp.

Such was the power of superheating (bad pun, sorry).  By the way, Mr Manson reduced the boiler pressure on Nos. 128 and 129, from the 180 psi of the '381' class, to 160 psi.

The royalties required to use Schmidt superheaters made some locomotive engineers file patents for their own fire tube superheaters - these all worked on the basic Schmidt principle - and this accounts for the use of terms like 'Robinson superheater'. Superheaters became fairly widespread in use, led, in numbers, by the GWR, LNWR, NER and Midland.  After the end of the Great War, fire tube superheating was the norm for most express passenger locomotives and many others.  The Furness Railway remained an exception, even on its 4-6-4T engines.

These superheaters generally corresponded reasonably well with Dr Schmidt's recommendation to equalise the free gas area through the flue tubes and boiler tubes - the 50/50 ratio.  The NER experimented with a ratio of about 60/40 on the three-cylinder 'Z' class 'Atlantics' (later, LNER 'C7') from 1913, but this reverted to a more 'normal' ratio in LNER days - the 20 per cent reduction in evaporative heating surface was found to be too much.

Older designs were sometimes reboilered with superheaters, a good example being Mr Urie's reboilering of Dugald Drummond's LSWR 'T9' class.


(https://www.ngaugeforum.co.uk/SMFN/gallery/143/6222-310724121003.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=143743)

[I don't think the extended smokebox and Urie chimney help the looks of the 'T9' but they made it a better engine.]


I am conscious that I have been guilty of a 'dog that did not bark in the night-time' approach to Mr Churchward's 'Swindon superheater', patented in 1908, and the subsequent GWR policy that prevailed until 1944.  For me, sitting here, between the Forth and the Tweed, commenting on Great Westernry might be considered presumptuous, at least.

But, unless anyone else cannot resist taking that particular nettle in hand, I'll attempt to cover it in the next part, which will be the last in the boiler and firebox section.  We have got to the point where there is steam ready to do some work and, by the end of the Great War, that is likely to be superheated steam, in the big engines at least, sitting in the superheater header and awaiting our pleasure.  After our Great Western discussion, we will, hopefully, get on to the engine part of the locomotive in Part 42 of this mini-series.

If there is a bit of a hiatus, it's because Mrs Poppingham and I have COVID - four-year-old newsingtons for to-day. Perfik!


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Pip-pip

John

Thank you for another fascinating post. I hope you and Mrs P. get well soon.

All the best,

Ali

Hope you both recover quickly and there are no after effects.

Best Wishes and Take care

Quote from: chrism on July 31, 2024, 03:48:39 PMBut could that not be that the superheater improvements enabled a greater steam delivery rate to the cylinders, allowing larger cylinder to be fitted and, therefore, an increased power output?

According to Wikipedia, as well as the cylinder diameter increase, they also increased the grate area, evaporative surface area and superheater surface area, all of which would help to create more steam to suit the larger cylinders.

I have read through my literature about Prussian locomotives, the "bible" Preußen-Report (vol. 2, 5, 6 – express, wet steam goods and superheated goods engines), and right from the beginning a reduction of coal and water consumption was expected as well as an increase in power.
Condensation was considered to be so severe that only 2/3rds of the generated steam would perform work in the cylinders of conventional steam locomotives, with wet-steam compounds doing slightly better at 3/4s. However, at the same time it was expected that the superheated steam would generate more power and thus larger cylinders were fitted as well.
 
But the sizes of cylinders, grates and boiler/superheater were all trial and error on both the express 4-4-0, class S4, and the goods 0-8-0, G8. There were still further enlargements and modifications after the S4 and G8 – but these larger engines were then considered new classes, S6 and G8.1.


I just noticed that there may be a bit of misinformation here. (But then the Prussian tangent is not really that important on this thread.)

QuoteAfter some years of experimentation, initially with smokebox superheaters (please see Part 38 to find out about these), Wilhelm Schmidt designed a practical fire tube superheater.  The first was fitted to a Prussian State Railways' (KPEV) 'G8' 0-8-0 in 1902.

According to the Preußen-Report vol. 6, the first installation of the fire tube superheater was in 1903 on the LAG (Lokalbahn AG Munich) 2-6-0 No. 18.
The G8 was built with the earlier smokebox superheater (which was also a Schmidt design) from 1902 to 1906. Only from the 154th engine in 1906 was the newer fire tube superheater used on the G8.

Thank you very much, Peter.  That came from a normally-reputable source.  But a British source.

At least it acknowledged Dr Schmidt's earlier involvement with smokebox superheaters and gives him full credit as the inventor of a working fire tube superheater.

You might find references to the LB&SCR 4-4-2T which mention the superheater but fail to acknowledge the rest of Dr Schmidt and his company's contribution.  Apparently, he set the valves on the first engine himself.

Thanks again and all good wishes.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 41


Hello Chums

Very special thanks to Peter @Hiawatha for his helpful contribution.

*

Right-oh - fools rush in and all that jazz.  Great Western Railway and superheat.  What's the story.  I'm not an expert on anything, especially the Great Western.  But, we have seen something peculiar going on the pre-Great war period.  Let's see if we can make sense of it together...please contribute.  Even if it's to tell me I'm a half-wit.

We have established the basics of the eituation, I think, as:

Mr Churchward disagreed with many of his contemporaries regardin high boiler pressures - he established 225 psi as a standard for large engines.

Some other engineers saw superheating as, in part, a way to reduce boiler pressures and, they though, cost.

For reasons that we'll examine in the third section, about the engine, GWR locomotives were head and shoulders above those on other railways until the 1920s.  Interrchange trials on the LMS and LNER proved this.  The LMS even asked the GWR to build it some 'Castles'.  This was declined.  Just as well, the private locomotive manufacturers would have gone to court quicker than one can say "Swindon Works" if this had happened.

Great Western engines were optimised to burn Welsh bituminous steam coal mined in the area between the (Newport) Western Valleys and the Aberdare/Rhondda Valleys.  This coal is the stuff of legend and is not anthracite.

Finally, a couple of new points.  Superheating was to a great extent enabled by reliable piston valves - can we please take this 'as read' as it's one for the next section?

Also, by massive improvements in another industry - oil technology.  Mrs Poppingham's Honda 'Jazz' motor car has a performance far in excess of what one would expect fifty years ago.  And, it's an 'old person's car' not a sporty thing.  I can assure you it runs on fairly fancy oil.  My old OHC Norton 'Singles' like 'Castrol R' and I like the smell it makes.  We used to pour a dash of cooking oil into the petrol tank of our 250cc BSAs and suchlike so they smelt like 'Gold Stars'.

Superheating required oil to withstand the higher temperatures being achieved and these were coming on the market at a convenient time.

Let's assume Mr Churchward was Great Britain's second most innovative locomotive engineer and he most certainly knew what he was doing.

Ands, another one for the next section. but I'll mention it on passing so you are aware I know about it.  Mr Churchward favoured long piston strokes.

*

The one thing Mr Churchward was keen to avoid was steam condensing in the cylinders so he set the 'Swindon superheater' to give a temperature to achieve this.  Then built a lot of superheated engines - 750 by 1912; about a quarter of the company's locomotive stock. The LNWR was next with 200.

Why did Mr Churchward stick to the two row superheater giving an approximately 30/70 flues to boiler tubes ratio?


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

John

Quote from: Train Waiting on July 31, 2024, 09:43:17 PMWhy did Mr Churchward stick to the two row superheater giving an approximately 30/70 flues to boiler tubes ratio?

Presumably he found that that ratio gave him the best option for sufficient evaporative surface and superheating.

As I said previously, adding superheater flues reduces the number of small tubes that can be fitted and, thus, the overall evaporative surface. If the boiler can't make sufficient steam in the first place there's no point in superheating it.

One thing not mentioned in the once again excellent posts are snifting valves.

AFAIK, these were not fitted to saturated engines, but were on superheated ones to allow air to circulate with regulator closed.

It was appreciated by locomotive engineers that when the regulator was closed when running, the cylinders would act like a vacuum pump drawing smoke box ashes back into them; also, with the regulator closed and hence no steam flow through the superheater tubes, these tubes would be 'dry' and prone to overheating. The answer was to fit a valve-frequently in pairs, so that when the regulator was closed, outside air would be drawn into the superheater tubes to keep them 'cool'.

There were variations in design; a common one looked like the 'pepperpot', another like a mushroom. these were usually in pairs (one for each cylinder?) with one each side of the smokebox top and behind the chimney.

Mr Gresley's design was was usually, at least in multi cylindered locos, a single circular perforated unit placed just behind the chimney.

Some CMEs officially required the regulator to be left just open and allow a minimum steam flow through the superheater and cylinders when coasting, but observations suggested that this was not always what happened 'on the road'. When the snifter valves worked, they chattered as air was drawn in, and of course, were one way so that steam could not escape back to atmosphere when the regulator was opened.

Thanks again, John, and I hope I haven't jumped the gun on this one.

Martyn

Regarding the later LNER pacific boiler policy, amongst other facts, the RCTS book says;

(Peppercorn A2); the boilers of the A1 and A2 had a smaller [tube} heating surface...but a larger firebox heating surface. This meant a more rapid evaporation only resulted in wet steam carried over.....where the superheater was inadequate to raise the temperature sufficiently. .......this highlighted the fact that Doncaster's policy with [later pacific] boilers was wrong, as each new variety of high pressure [250psi] boiler had an identical tubing arrangement whether the barrel was 16' or 19' long. Deficiencies were masked by employing as large a firegrate as possible....and ignore subsequent higher coal consumption'.

To be added to.

Martyn

I'm so sorry, chums.  In my Covid befuddled state last evening, I managed to press 'post' rather than 'save draft'.  Hence the curt ending which I've tried to ameliorate to-day.

I'll continue with the postington (possibly with another one) but it won't be to-day.

Sorry for the mess-up.

Covid is such fun!

With all good wishes

John   

No worries, mate. All will be well.  :thumbsup:

A final (I hope!) tail lamp to the later Doncaster Pacific boiler designs.

The RCTS again;

Class A2/3 on trials against V2;

'it was noted that whereas the surface heating figures were identical.....the temperature of the smokebox gases in the A2/3 were higher, ie more heat was lost through the chimney.....this was assumed to be due to an imbalance in the size of firebox and boiler barrel. ......although the temperature of the superheated steam was higher in the A2, it was not sufficiently so to benefit from the higher boiler pressure. '


However, both the Thompson and Peppercorn types could generate 2000hp+, which was of use handling the heaviest trains.

It goes on to say what I have posted before, that the larger firebox was later deemed wasteful of coal, water, and power, and could only be used to advantage on the heaviest trains. This latter is repeated in the chapter about the Peppercorn Pacifics, which were developments from the Thompson designs. They were less economical than the A4s on similar duties; it is to be remembered that the A4 boilers were a development of the A1/A3 boiler, which was itself scaled from the Pennsy K4 which had been extensively tested before entering service, and has been mentioned in the thread before. The later Pacific boilers had lost the relationship between firebox, small tubes, and superheater that had been evolved for the other classes.

Hope at least some of you are still interested! It does shown what a complicated relationship there was/is between the various parts of a steam loco.

Martyn

Blimey! My head is definitely beginning to hurt. So much I don't know...

Thanks all!

Cheers,

Chris

Quote from: Papyrus on August 01, 2024, 08:07:17 PMBlimey! My head is definitely beginning to hurt. So much I don't know...

Thanks all!

Cheers,

Chris

Do you remember a few years ago when a bunch of British plane spotters were arrested near a Greek military airfield? They were locked up for days. Unfortunately for them, their interrogation began with the question, "Tell us everything you know ...."

Mike

A short addendum about snifter/snifting valves.

By no means all superheated locos had them. Some had them for only part of their life.

The LNER used them extensively; the SR used them but were later removed.

See

https://en.wikipedia.org/wiki/Snifting_valve

for a better explanation than I gave!

Martyn

 I'm surprised that our friend John@trainfish has not commented on this as he has been known to enjoy a snifter from time to time ?

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 42


Apology and a Feeble Attempt at an Explanation

Hello Chums

For ages now, I have been acutely aware that I abandoned this mini-series in a rather abrupt manner. I'm very sorry for this. My last postingtons were when I had contracted Covid which, incidentally, was worse than when I had it in 2021.  Much worse.

I had the next part drafted and the one after that saved in note form.  But I lost both due to the 'seven days for drafts rule' that came in with the last Forum upgrade.  Bother!

Then the disagreeable series of treatments I was receiving for my recalcitrant legs was suspended, followed by an appointment where a charming lady hit me with a hammer for half-an-hour and then stated, "It's getting worse." I'm now on a waiting list to get onto another waiting list for the nice people to decide what they want to do next.

All of this rather put me on the wrong side of the drag curve as regards motivation.  A sort of engine ennui.  But, up with this I cannot put.  No wimpish sniffling self-indulgence allowed. I decided to recommence the mini-series before the end of the year.  Our FabulousForum cautioned me against returning with this SuperStern massage:-

'The message has the following error or errors that must be corrected before continuing:
Warning: this topic has not been posted in for at least 120 days.
Unless you're sure you want to reply, please consider starting a new topic.'

Yes, bossy old thing, I'm sure I want to reply. 

*

On with the mini-series...


We sort of left off with my rhetorical question:

Quote from: Train Waiting on July 31, 2024, 09:43:17 PMWhy did Mr Churchward stick to the two row superheater giving an approximately 30/70 flues to boiler tubes ratio?

Many thanks to @chrism and @martyn who kindly replied.

I think the answer is clear - Mr Churchward's locomotives were head and shoulders (at least) above anything else in this country.  And this would remain the case until he retired in 1922.  I think there was an exception, Mr Maunsell's 'N' class 2-6-0 on the South Eastern & Chatham Railway.  We'll likely return to these locomotives later.

For just over twenty years, from his standardisation proposals of 1901 until his retirement, Mr Churchward led British steam locomotive development. Then Mr Collett took over as Chief Mechanical Engineer and remained glued to the 'Churchward Principles'.  And, he almost got away with it. In my view, the disruption came with the Second World War.  No longer could the world's best steam coal, expert enginemen and fastidious maintenance be depended upon.

Mr Collett retired in 1941 and it fell to his successor, Frederick Hawksworth, to try to find a way to adapt GWR locomotive policy into a railway world which had changed forever. Mr Hawksworth tried outside valve gear on the '15xx' 0-6-0PT locomotives and high boiler pressure (280 psi) with his 'County' 4-6-0 class.  But, to my mind, his most important contribution to Great Western locomotive development was his introduction of higher superheat.

And, nowhere was this more obvious than with his developments of Mr Collett's 'Castle' class 4-6-0s.  Since Mr Churchward's day, the pretty much standard arrangement for superheating on GWR 4-6-0 locomotives was 14 flues, arranged horizontally across the boiler, towards the top, in two rows of seven.  Hence the term, 'two-row superheater'.  This gave around 260 sq ft of superheater surface area.  In other words, over the 260 sq ft, the steam in the superheater elements was exposed to the heat of the gasses from combustion passing through the flues.

Meanwhile, on the Southern Railway, Mr Maunsell's 'N15' 'King Arthur' 4-6-0 class of 1924 featured 337 sq ft of superheating surface and his larger 'LN' 'Lord Nelson' 4-6-0 class of 1926 featured 376 sq ft.

Over on the LMS, not generally considered to be at the forefront of locomotive development in Sir Henry Fowler's time, the 'Royal Scot' 4-6-0 class of 1927 had a superheater surface of 399 sq ft.

But such was the excellence of Mr Churchward's legacy in other areas that the low superheat did not prevent GWR locomotives demonstrating their superiority over those of other railways. The tests of a 'Castle' on the LNER in 1925 and the LMS in 1926 gave conclusive proof of this and led to interesting developments in locomotive design on both these railways.

However, steam locomotive operating conditions in the nineteen-forties were significantly more difficult than in 1926 and Mr Hawksworth set out to improve the performance of the 'Castles'. He had already introduced a higher degree of superheating with his '6959' 'Modified Hall' class of 1944 and '1000' 'County' class of 1945.  Both of these featured three-row superheaters with 21 flues.

No. 5097 was the last pre-War 'Castle', entering service in September 1939.  Passage of time and the difficult wartime conditions meant that, by 1945, the remaining 'Star' class locomotives were becoming worn out.  Mr Hawksworth obtained authorisation for the last 40 'Castles', Nos 5098 - 7037, which entered service between May 1946 and August 1950.

[Fun Fact.  Not all 171 members of the 'Castle' class were in service at the same time.  And, thankfully, it's not due to one being destroyed in an accident or by enemy action. No. 100A1 Lloyds, one of the 16 'Stars' rebuilt as 'Castles', was withdrawn in March 1950. The final batch of ten 'Castles', Nos 7028 - 7037, entered service between May and August 1950. And, one would have had to be quick off the mark to see the maximum of 170 locomotives in service as the next two, again, rebuilt 'Stars', were withdrawn in September 1951. ]

Back to No. 5098 Clifford Castle - she, like the other post-War 'Castles', was outshopped by Swindon with a three-row superheater.  She was regarded by many enginemen, at the time she entered service, as the best 'Castle' built.

Mr Hawksworth retained the Great Western concerns about the lubrication of locomotives with higher superheat and lubrication arrangements were changed with effect from No. 7000, which also entered service later in May 1946.  Nos 5098 and 5099 later had their lubrication arrangements changed to the new type.

Right at the end of the Great Western's existence as a company, in 1947, Mr Hawksworth had No. 5049 Earl of Plymouth fitted with an experimental four-row superheater.  In BR days, commencing in 1957, four-row superheaters were fitted to more of the class, finally reaching a total of 65 locomotives by the end of 1961.

Finally, following Mr Hawksworth's trial of a four-row superheater on No. 6022 King Edward III in 1947, the remainder of the 'King' class were fitted with four-row superheaters during the period 1949-1951.

*

I have mentioned before the difficulty of discussing parts of a steam locomotive in isolation.  I touched upon lubrication in this postington but ignored double chimneys.  These subjects are for consideration later.

Just one part more on boilers, specifically superheating, where a famous engineer was slightly caught out by the Churchward legacy, and then we'll get onto to the section about the engine itself.  Or, if you prefer, engines themselves.  I'll attempt to explain later.

*

Coda

The final development of the 'Castle' class was truly a magnificent locomotive and well adapted to post-War conditions.  In Portraits of 'Castles'* by Bryan Holden and Kenneth Leech, there is, on page 12, this interesting snippet.  It refers to No. 4090 Dorchester Castle, the first of the class fitted with both a four-row superheater and a double chimney.  The authors refer to her as being a 'remarkable engine'.  Then they add:

'Qualification of her performance is necessary because enginemen who had worked the 1932** 'Castles' which had made history on the 'Cheltenham Flyer' held firm to their opinion that the engines in those days were every bit as good as No. 4090.'

Allowing for a nice mixture of rose-tinted glasses and nostalgia, the enginemen made, in my view, a valid point.  A Churchward-style locomotive was, in its day, a magnificent machine.  However, post-War performance of the 'Castle' class was, due to the factors mentioned above, diminished and the modifications commenced by Mr Hawksworth and continued by KJ Cook and RA Smeddle restored them to well deserved excellence.


* Portraits of 'Castles', Bryan Holden and Kenneth Leech, Moorland Publishing, Ashbourne, 1981 ISBN 0 903485 89 3.

** Ten of the class were built in 1932, Nos 5013 - 5022.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-bye

John

A very welcome return of this excellent and informative thread, thank you John.

All the very best,

Tim (back from the mists of Agincourt!)

Good to see your wonderful series returning.
I wish you all the best for 2025.
Cheers :beers:

Welcome back, John, to your highly entertaining dissertation. So sorry to hear you have been bothering the NHS. I hope it all gets sorted soon.

Quote from: Train Waiting on December 29, 2024, 10:15:23 AMI had the next part drafted and the one after that saved in note form.  But I lost both due to the 'seven days for drafts rule' that came in with the last Forum upgrade.  Bother!

For what it's worth, I have devised a solution to this problem. Whenever I want to commit something to the Forum which requires a bit more thought than I am accustomed to, I draft it in MS Word first. Then, when I am satisfied with the Beauty and Lucidity of my prose I copy and paste it to the appropriate section of the Forum. That way you can work on it over a period of time without worrying whether it will disappear into the ether.

Anyway, your latest work was worth the wait as always, even though the GWR holds no interest for me whatsoever. That is obviously a severe character flaw on my part which I shall make no attempt to rectify.

Looking forward to the next chapter.

All the best,

Chris

I think that there will soon be posts which are more deeply connected to the LNER, Chris.

But it was the Castle trials against an A1 which directly led to the improvements in the latter, (led by Spencer and with Gresley seemingly not fully convinced), and then development into the A3, which was, performance wise, much better than the A1 and which the Castle could, possibly, not match, though the last development of the Castles might have been very close. We'll never know the latter, though...

Martyn

Many thanks, Chums.

My computer-thingy doesn't have MS 'Word', so, unfortunately, I'm not able to use it for for drafts.  But, it sure looks like a wizard wheeze for those with it at their fingertips.  I'm wondering if my drafting postingtons on locomotive draughting will finally cause our Fabulous Forum to blow up.  We'll see.  We'll even meet a Finnish chap, later on, which might be a fitting way to finish [Thank you!] the mini series.

Yes, indeedy, there will be lots 'N' lots of lovely LNER stuff to come.  But not yet.  Our attention in the next part is firmly on the LMS.  I know: I've just made it up written it following diligent and fastidious research.

With regard to GWR engines and any lack of interest thereof:-

Firstly, it's not compulsory.

Secondly, listen (with eyes firmly closed if necessary) to a GWR engine accelerate a train away from a station on a gradient - Keighley is a good example.  The purity of the exhaust sound is deeply moving.

Thirdly, Sir Nigel Gresley was unsparing in his praise of Mr Churchward.

Next part soon...

Thanks again and all good wishes.

John

Train Waiting: try Libre Office, it is freeware and the equivalent of MS Office.
It runs well on Linux too!
Cheers

Quote from: Firstone18 on December 29, 2024, 10:33:49 PMTrain Waiting: try Libre Office, it is freeware and the equivalent of MS Office.
It runs well on Linux too!
Cheers

Alternatively, Google Docs. Free. Nothing to install. Wordy. Works on anything connected to the internet.

https://docs.google.com

Their 'Sheets' (Excelish) and 'Slides' (Powerpointy) are also very good.

Mike

Or, even, Notepad (or whatever similar Apple include)

I don't do any of that myself, even though it makes infinite sense. I've lost many a post I've typed into the forum.

Anyway this is starting to look like a thread hijack of what is the most brilliant thread here! :beers:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 43


A Little Difficulty on the LMS

Hello Chums

I expect you know the story - by 1931, eight years after the Grouping, locomotive affairs on the LMS were not wholly satisfactory.  There had been some in-fighting and the Motive Power Department, which was separate from the Chief Mechanical Engineer's Department, was heavily influenced by Midland Railway practice going back to the time before the Great War.  George Hughes, from the 'enlarged' LNWR and before that the LYR, was the first Chief Mechanical Engineer (CME) from 1923 until he retired in September 1925.  He was succeeded by Sir Henry Fowler, previously of the Midland, who had been Deputy CME of the LMS since the Grouping.

The 'Fowler Years' saw a lot of interference and less progress than would have been expected.  The LMS Board recognised this, shunted Sir Henry into a Research Department siding and appointed Mr EJH (later, Sir Ernest) Lemon as CME in January 1931.  This was an acknowledged interim measure as the Board had asked Sir Harold Hartley FRS, of Balliol College, Oxford and recently-appointed Vice-President and Director of Scientific Research of the LMS, to find a suitable person to be appointed as CME.

WA (later, Sir William) Stanier, Principal Assistant to the CME of the GWR, was the chosen individual and he commenced as CME of the LMS on New Year's Day 1932.

Amongst a generally lacklustre group of locomotive types introduced on the LMS from 1923 to Mr Stanier's appointment, four, in my view, shine out as rather good engines:

'Horwich Mogul' 2-6-0 of 1926 - essentially designed under Mr Hughes;
'4P' 2-6-4T of 1927;
'Royal Scot' 4-6-0 of 1927 and
'Patriot' or 'Baby Scot' 4-6-0 of 1930 - the first two were nominal rebuilds of ex-LNWR 'Claughtons', the remaining 50, under Mr Lemon's direction, were new engines.

*

The LMS Board had been eager for the LMS to have Swindon 'know-how' at its disposal and Mr Stanier's first four designs, introduced in 1933 and 1934, were much influenced by the Churchwardian design philosophy.  They were:

'Princess Royal' 4-6-2
'5MT' 2-6-0
'5XP' 4-6-0 - generally known as the 'Jubilee' class but, of course, King George V's Silver Jubilee was in 1935, after the class was introduced;
'5MT' 4-6-0 - the immortal 'Black Fives'.

The first examples of these classes featured typical Swindon two-row superheaters. This was a conscious decision, due to the superior GWR-style taper boilers which Mr Stanier intended to use. Let's quote ES Cox, who was in the CME's Department at the time:

'Stanier firmly believed that the arrangement of steam and water spaces gave, in combination, advantage in steam production.  He explained to us that these elements would counterbalance the effects of low degree superheat which was a feature of Swindon practice and which he now applied to all of his first designs for the LMS.'¹

In practice, the 2-6-0 and the 'Black Five' worked well, especially the latter.  Both were straightforward two-cylinder designs very much in the Churchward tradition.

Only two 'Princess Royal' locomotives were built at first and these prototypes struggled to live up to expectations, especially with regard to steaming.

The '5XP' or 'Jubilee' was Mr Stanier's development of the 'Patriot' class and, with them, he ran into serious trouble.  The requirement for the locomotives was urgent and he did not build any prototypes, instead, 90 were built 'off the drawing board' in 1933 and 1934.  They turned out to be poor steamers and nowhere as good as the 'Patriots'.

To quote ES Cox again:

'A situation arose, therefore, which was very serious for a while, and there was considerable recrimination from the motive power and operating sides [Departments]'²

Quite.


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-291224165301.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148048)

[A '5XP' or 'Jubilee' 4-6-0.  This one is by Rivarossi for Peco and her performance has not resulted in 'considerable recrimination'.  Quite the opposite, in fact.}


But, what was wrong?

It's always nice to quote from David L Smith, who saw these engines at work in Scotland 1935:

'A Newton Heath fireman, leaving Glasgow Central with the 4.30 pm, told me to watch the exhaust as they pulled out.  Sure enough, in the centre of the column of white steam was the thin black column of water, like the lead in a pencil.'³

Being a good engineer, Mr Stanier did not forbid criticism of his designs and the problems were identified.  The 'Patriots' had 24 flue superheaters, but the new design had the traditional Swindon two-row, 14 flue superheater with a surface of 227 sq ft.  It was found that this resulted in a 100^oF (38^oC) reduction in steam temperature compared with the 'Patriots'.

After a series of experiments, and considerable development of other parts of the boiler, a 24 flue superheater became standard for these engines, increasing the surface to 307 sq ft. Still, in my view, on the low side for the time.

Incidentally, there were other important changes made, but these are outside the scope of this part.  I've a feeling we'll return to them later in this mini-series.

These lessons weren't lost on the 'Princess Royals' - the 10 'production series' locomotives were delivered in 1935 and had four-row, 32 flue superheaters.

For the 2-6-0 and the 'Black Five', larger, 21 and 28 flue superheaters, respectively, became standard.  These gave the mixed traffic 'Black Fives' a superheater surface of 359 sq ft - significantly more than the express passenger 'Jubilees'.

The lessons were not lost on Mr Stanier and his magnificent 'Princess Coronation' 4-6-2s of 1937 had five-row 40 flue superheaters, with a surface of 856 sq ft.  I understand this was the highest superheating surface area of any British locomotive.

*

I found an interesting epilogue to this part in JE Chacksfield's C.B. Collett A Competent Successor:

'In 1935, Collett received a note from Stanier, now well-established on the LMS. In the note was the revelation that the application of low-degree superheat on the LMS was not particularly successful and in investigations to try to overcome the short-comings, it had been noticed that the area for the passage of steam through the 14 flue superheater tubes was less than the area of the main steam pipe from the regulator. Stanier had been led to this by his attention being brought to continually low steam chest pressures. On changing to a 28 flue superheater a dramatic change in performance had ensued.'⁴

*

Thank you for your understanding regarding the delay in completing the 'boiler' section of this mini-series.  The next section will, hopefully, commence next year.


¹ ES Cox, Locomotive Panorama Volume 1, Ian Allan, London, 1965. Page 103.

² ibid. Page 106.

³ DL Smith, Legends of the Glasgow & South Western Railway in LMS days, David & Charles, Newton Abbot, 1980 ISBN 0 7153 7981 X. Page 87.

⁴ JE Chacksfield, CB Collett A Competent Successor, Oakwood Press, Usk, 2002 ISBN 0 85361 586 1. Page 85.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John 
 

   

As usual, amazingly awesome. Thank you, John!!

 :beers:  :thumbsup:

Gresley was aware of restricted steam passage design, and when designing the A4s made sure that two right angle bends in the A1/A3 cylinder arrangement were eliminated and that the bore of the pipes was sufficient, even ensuring that pipe joins didn't have tiny internal 'flanges' or casting faults to restrict steam. This ensured that effectively 100% of boiler pressure was available in the steam chests at fully open regulator.

It was said that the 'Kings' had a reluctance to run really fast consistently, and it has been suggested that this could have been due to internal steam pipe clearances. They were a better riding loco than the 'Scots', though. The original 'Scots' seem to have been a mixture of Derby and North British Loco practice, with a bit of the Southern 'Lord Nelsons' thrown in.

I've seen it said that the 'Black Fives' were so named at the time to distinguish them from the 'Red Fives'-the 'Jubilees'.

I've also seen in print-jokingly, I think-that Swindon didn't really design any new engines from Churchward to the 'County' class; they just looked around and saw what Churchward had already designed for boilers, cylinders, and wheel sizes and just did 'mix and match'.

Not quite true, perhaps.......

But certainly Churchward and his team at Swindon were well ahead of contemporary loco practice and other designers followed some of his principles.

Thanks again for another wonderful lesson, John, and look forward to the next ones.

Martyn

Quote from: Train Waiting on December 29, 2024, 10:15:23 AMan appointment where a charming lady hit me with a hammer for half-an-hour and then stated, "It's getting worse."

Well you were advised, John, that 'Nurse Whiplash' did not sound like a genuine healthcare professional.
PW

Sorry to go back a few posts, but the RCTS LNER history does point out that the 'Castle' class had had seventeen years of development through the 'Star' class before the trials against the A1: which had only three years development.

However, there is no doubt the A1 was well behind the 'Castle' performance.

And the trials of the latter on the LMS effectively killed the proposal for a Derby designed Pacific, which wouldn't appear on the LMS until the Stanier era.

Martyn

Great series of articles!

Quote from: Train Waiting on December 29, 2024, 08:12:06 PMMy computer-thingy doesn't have MS 'Word', so, unfortunately, I'm not able to use it for for drafts.  ...

If your computer is Windows, you can use Notepad, which is part of Windows. Tap the windows button, and type "NOT" and it should appear. If you use a Mac, there is, I think, an equivalent called TextEdit.

Both are very basic, but perfectly fine for writing a draft for a forum post.

Well, I have just spent a few lunch breaks wading through this thread and I have to say @Train Waiting that this is an incredible work, and very engaging. I now understand far more than I ever did about those water boiling devices that my diesel-soaked brain would ever admit to, and I am now far more inclined to purchase a 'kettle' for my layout.
I am torn, however, between a Castle, a Black 5, a Bulleid or an A4. Maybe I should buy one of each?

Quote from: Foxhound on December 31, 2024, 02:12:08 PMI am torn, however, between a Castle, a Black 5, a Bulleid or an A4. Maybe I should buy one of each?

Yes.  This.  Actually, you've given me an idea, The only one I don't have is a Black 5 (how did that happen?).

Wonderful latest article John, I'm slowly beginning to understand the purpose and importances of a good superheater.  I have always been a huge fan of Castles (I think a far more effective and useful locomotive than the Kings, pound for pound) and I think Martyn's addendum about the pipe interior and shape considerations was very insightful and something I've not thought about before

Graham

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 44


Hello Chums

At Last, We Get to the Engine/s

Please think of a fire engine.  What did you imagine?  A big red lorry rushing round skooshing water at conflagrations?

In the second decade of the eighteenth century, it meant something different.  You see, in 1712, Thomas Newcomen developed a practical 'Atmospheric Engine' which was often called a 'Newcomen Fire Engine'.  Nowadays, we generally refer to it as a 'Newcomen Engine'. This is generally accepted as the world's first successful steam engine.

As is so often the case, Mr Newcomen had at his disposal the work of others who had experimented with various steam contraptions over the years. Worth mention is Denis Papin FRS, who had experimented with an atmospheric engine which used a piston moving in a cylinder.

The Newcomen engine works by drawing steam at about 2 psi, generated in a boiler below the engine, into a vertical cylinder. Once the cylinder is full of steam and the piston is at the top, the exterior of the cylinder is sprayed with water which condenses the steam.  This creates a partial vacuum in the cylinder which allows atmospheric pressure to push the piston down the cylinder.

The main use for Newcomen engines was to pump water out of mines.  The piston was connected to a rod which, in turn, was linked to a horizontal beam, pivoted in the centre.  The other end of the beam was connected to the pump. Many of these engines were built during the eighteenth century and they are regarded as the beginning of commercial steam power.

James Watt made many improvements to the Newcomen engine and is particularly remembered for the invention of the separate condenser.  In partnership with Matthew Boulton, their firm, Boulton & Watt, became leading builders of steam engines.

Mr Boulton was, it seems, keen to exploit steam power beyond pumping mines and encouraged James Watt to develop an engine where the reciprocating movement of the piston could be made into a rotary motion for driving machinery and suchlike.

Whilst a crank would have been the most simple solution, a chap called James Pickard had been granted a patent for the arrangement they would have used.  This caused them to devise a 'sun and planet' gear in 1781.  Steam power quickly moved from mines to manufactories and the industrial revolution was proceeding apace. Although he had a patent for a high pressure steam engine, the term was relative and James Watt resisted the use of substantially higher steam pressures on safety grounds.   

Although a footnote to history, it would be wrong not to mention Nicolas-Joseph Cugnot, a French military engineer, who built what is accepted as the first self-propelled mechanical land vehicle. Known as the fardier à vapeur it was, effectively, a steam-powered cart.  During 1769-1770, he built, I believe, three prototypes, two of which were full-sized.  The drive from the piston to a wheel was by means of a ratchet apparatus.

I have used three terms, in that brief overview of developments, to which I wish to return briefly.  These are the vital components which turn a xxxxx (please insert your own favoured type) from a boiler on wheels into a steam locomotive.

Cylinder, piston and crank.  Interestingly, the concepts go back about a couple of millennia, and they were in use in Roman times.  Although not quite as we'll be using them.  Still, the basic components of a steam engine were nothing new.

Waggonways, primarily to allow a horse to pull a heavier load, usually of coal, had been around for centuries and became fairly common after 1700.

Once James Watt's patent expired, Richard Trevithick led the way in the use of higher working pressures, around 30 psi (sometimes, during the period, called 'strong steam') from 1800. James Watt did not approve.

All these developments came together in Merthyr Tydfil, on 21 February 1804, when Richard Trevithick demonstrated the world's first steam-powered locomotive hauling a train along the tramway of the Penydarren Ironworks.  And, nearly two-and-a quarter centuries later, we are still building steam locomotives.  Hats off to Trevithick.

It's a great shame he never achieved the commercial success he deserved and ended up, in 1827, penniless on a quayside in South America.  Incredibly, he met, literally, with good fortune because (you know what it's like to go away on holiday and meet one's neighbours) he met Robert Stephenson.  As you might have noticed, I hold the Younger Stephenson in exceptionally high regard.

Mr Stephenson paid for Richard Trevithick's fare for the voyage home. History records he gave Mr Trevithick £50.00.  In to-day's money, that's getting on for 2,500 of these:-


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-010125125357.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148147)


For the next part of this mini-series, I'll fast forward through the period of the earliest steam locomotives, what I call 'Steam Dinosaurs', and centre our discussion on the 'engine/s' part of the kind of steam locomotive we might run on our layouts or see at a heritage railway.  However, before getting into all that, I was keen to note the historical context with a special mention to Richard Trevithick.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-pip

John

Many thanks for the latest instalment, John. The early history of the steam engine is a fascinating subject. As with so many other things, the real pioneers like Newcomen and Trevithick are often overlooked and those who are remembered today were the ones who 'stood on the shoulders of others', to quote Isaac Newton.

Your mention of the Cugnot steam cart brought back a memory from my teenage years. I built a plastic kit of one (can't remember the maker now) and I had completely forgotten about it until now. Naturally, I consulted Professor Google and came up with this (https://www.supercars.net/blog/1769-cugnot-steam-tractor/). I hadn't realised one was still in existence.

Cheers,

Chris

Fascinating stuff, John. :beers:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 45


Hello Chums

Before we time-travel over centuries in a sentence, I'd like to pause for a second to thank you for the thoroughly kind comments which you have posted since the mini-series recommenced. And, of course, for the 'reactions'.  These are hugely appreciated and encourage me to continue. Right-oh; on with the mini-series, where were we...

From the Ancients to the Steam Shed

We saw, in the previous part, that the key components of a steam engine: cylinder, piston and crank were known about and were being used, albeit for different things, when BC became AD. (No, I'm not in favour of the terms BCE and CE.)  The other component required to convert reciprocal movement to rotary motion and, indeed, vice versa is the connecting rod and there appears to be evidence that this was in used (in the vice versa sense) in Roman (at least) times to convert rotary motion to reciprocal to move power saws.

Cylinder - piston - connecting rod - crank: here we are fast-forwarded:-


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-020125115216.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148165)


From the rear of the cylinder projects the piston rod.  One end is connected to the piston which, I invite you to imagine, is inside the cylinder.  The other end is attached to the crosshead.  The crosshead is moved to-and-fro by the action of the piston and its movement is kept where it ought to be by it sliding along slidebars.  This locomotive has two prominent slidebars, one above the crosshead and one below.  Locomotive designers enjoyed different crosshead and slidebar arrangements, but the principle remains the same.

Pivoting on the crosshead is the small end of the connecting rod.  The big end of the connecting rod sits on the crankpin, which projects from the crank.  The radius of the crank is half that of the distance the piston moves in the cylinder - called the stroke.

In two paragraphs we have introduced reciprocal, pivoting and rotational movement, all of which requires suitable bearing surfaces and lubrication.  Think of the driver going diligently around the locomotive with his oil can.

At this point, if you have tinkered with old motor-bicycles or motor-cars during your life, you might wonder why the steam locomotive has a piston rod and a crosshead.  Internal combustion engines manage happily without these, having the connecting rod pivoted from a gudgeon pin in the piston.

There are two reasons for this:

1. The distance from the piston to the crank is a lot further in a steam locomotive.  Add to this the forces involved and there is a requirement for a long and heavy connecting rod.  It makes sense to have it well-supported at its small end.

b. This one is a fundamental point which we need to understand.  Pistons in an internal combustion engine are single-acting - they are forced in one direction by the mixture exploding and are returned by the crankshaft via the connecting rod.  A two-stroke engine has one power stroke for each revolution of the crankshaft and a four stroke engine has one power stroke for two revolutions of the crankshaft (assuming single-cylinder engines).

Please think about that.  For every four times the piston in a four-stroke internal combustion moves along the cylinder, it produces power once only.  The other three times, it is using power.

Newcomen engines and those derived from them had single-acting pistons.  Then James Watt transformed the situation by making the piston double-acting, producing power with each stroke.

And that's what a steam locomotive does - each piston stroke is a power stroke, which means the piston has two power strokes per revolution of the crank.  We'll discuss how this is achieved later but, for now, can we please accept that the clearances required to allow the connecting rod to pivot in the piston would be such that the steam would escape to atmosphere?

The steam engine has another advantage over an internal combustion engine.  Let me choose a motor-bicycle, say a Brough Superior 'SS100' vee-twin like TE Lawrence enjoyed.  I sit astride it, turn on the petrol, tickle the Amal carburettor, ease open the twistgrip and... Nothing!  I could sit there all day and nothing would happen.  Same for your petrol or diesel motor-car.

Of course, you could activate the starter motor and I could give the JAP engine a 'long swinging kick' with the kickstarter and we'd both be away.

Have you ever seen the fireman attempting to kickstart a '9F'?  Or seen the driver press the button for the electric starter?  No.

Why's that then? Because the double-acting steam engine starts itself when steam is applied.  Or, it usually does.

Clever stuff this, and please remember it's a technology that's a couple of centuries old.

Some of the earliest locomotives had only one cylinder but two quickly became the norm.  The disposition of the piston at top or bottom dead centre, and the subsequent location of the crank, might mean a single-cylinder steam engine was in a 'blind spot'.  Single-cylinder traction engines, should they suffer this inconvenience, can be given a little push on the flywheel and off they jolly well go.

A driver can still be unlucky with the disposition of the pistons of a locomotive, which might refuse to start, say, when leaving a station.  He would deal with this by putting the locomotive into reverse and moving back a tad, then into forward gear and away. So much easier with Jimmy Stirling's steam reverser as fitted to locomotives of the Glasgow & South Western and South Eastern Railways.

Next, we'll discuss where the cylinders are located (normally - no backwoods 'Shay' or other types will intrude).  Probably a little later, we'll even encounter locomotives with more than two cylinders.  Anyone know which British railway first introduced a four-cylinder locomotive?

Finally, you might have seen me use the form, 'engine/s', in a couple of previous postingtons.  It was just me hinting about something that might have become apparent from what I've written above.  Each cylinder - piston - piston rod - connecting rod - crank grouping on a steam locomotive is, effectively, an engine in its own right.  Perhaps, something worth keeping at the back of one's mind.  The point having been made, I'll use 'engine' from now on.


'N' Gauge is Such Fun

Many thanks for looking and all best wishes.

Tickety-tonk

John



   

A thank you from me John on the history and engineering lessons

Maybe you should be be a Railway author

Happy new year.  Chris

Thanks again, John.

As an aside, I think the big marine diesels of today are classified as 'trunk' (without crosshead-not sure, I was a navigator at sea....), or crosshead type, if so fitted.

I think also a two stroke of any number of cylinders fires once per rev, as opposed to once every second rev of a four stroke (?). (or maybe I've misunderstood your post).

There were/are a few designs of internal combustion engines that were double action, at least some marine diesels; and I think the ill-fated Kitson-Still loco was also double acting but with steam on one side of the piston and diesel on the other! However, it wasn't that simple, as steam at one end of the piston was used to start, and at 4 mph, diesel was injected into the other end of the cylinder and steam shut off.

Martyn

Quote from: martyn on January 02, 2025, 05:22:37 PMI think also a two stroke of any number of cylinders fires once per rev, as opposed to once every second rev of a four stroke (?). (or maybe I've misunderstood your post).

"A two-stroke engine has one power stroke for each revolution of the crankshaft and a four stroke engine has one power stroke for two revolutions of the crankshaft (assuming single-cylinder engines)" - I think you missed the bit in brackets.

Quote from: chrism on January 02, 2025, 06:04:35 PM

Quote from: martyn on January 02, 2025, 05:22:37 PMI think also a two stroke of any number of cylinders fires once per rev, as opposed to once every second rev of a four stroke (?). (or maybe I've misunderstood your post).

"A two-stroke engine has one power stroke for each revolution of the crankshaft and a four stroke engine has one power stroke for two revolutions of the crankshaft (assuming single-cylinder engines)" - I think you missed the bit in brackets.

Quite right, Chris.

Thanks for that.

Martyn

Thank you very much, Chums.

A four-stroke single only 'fires' one every second revolution of the crankshaft.  This leads to some interesting sounds. A 'Big Pussy' (Panther 650 cc ohv single - built in Cleckheaton) 'firing once every lamp-post', or a racing machine in Poppingham's time sounding like nothing else on earth.  No hairs left on the back of my neck.  The film features Stanley Woods on a Works 'KTT' Velocette 350cc ohc single.


 


I've owned several 'Velos' in my time, but only ohv models.

With all good wishes.

John

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 46


Hello Chums

Where to Put the Cylinders

Continuing from where we left off, discussing two-cylinder steam locomotives, there arises the matter of where to place the cylinders.  At the front of the locomotive is obvious, to allow an easy route for steam from the boiler, often called 'live steam', to get into the cylinders and for steam that has been used in the cylinders, called 'exhaust steam' to get away and straight up the chimney.  Please note, I an skipping gazelle-like around the matter of the Franco-Crosti '9F' 2-10-0s.  What a waste of money that wheeze was.

In the early days, the cylinders were outside of the locomotive's frames and there are pictures of these earlier in the mini-series.  Then Robert Stephenson had an idea - he placed the cylinders of his Planet 2-2-0 of 1830, for the Liverpool & Manchester Railway, between the frames.  This arrangement is what is known as an inside-cylinder locomotive.  The type dominated locomotive construction for British railways during the 19th Century and only gradually became less prevalent in the 20th Century.

*

Let's pause for a Fun Fact.

The last inside-cylinder tender engine to be built for a main line British railway was '2251''Collett Goods' 0-6-0 No. 3219, built for BR (WR) in January 1948.

Inside-cylinder tank engines were built even later, the final one for BR being '9400' 0-6-0PT No.9499 in July 1955.  She barely saw four years' service.

*

Now for a couple of picturinghams:-

An 'Adams 'Radial' 4-4-2T outside-cylinder locomotive:


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-020125154658.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148175)


And an inside-cylinder locomotive - a Hunslet 'Austerity' 0-6-0ST, this one being an LNER 'J94':


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-020125154735.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148176)


Can you imagine it?  Railway Bylines magazine Volume 30, Issue 2, January 2025, has a picture, on page 97, of a NCB driver standing beside an Austerity' 0-6-0ST.  The caption tries to persuade us the he is oiling the connecting rod bearings.  My emphasis.  A glance at @Nbodger 's splendid photograph (above) of his 'Austerity' leaves us in no doubt that she's an inside-cylinder locomotive with connecting rods between the frames.  The driver would have been attending to the coupling rods.

It's bad enough when modellers make that fairly common error of terminology, never mind Railway Bylines. 

And what about people wittering on about a train's 'consist'?  Fine for the Seaboard Air Line, but not 1950s BR.  Grrr!

*

Although inside-cylinder locomotive were, by far, the most common type during the 19th Century, their dominance was never complete.  Some designers preferred outside cylinders for at least some of their locomotives - a good example being William Adams, best known for his work on the London & South Western.  They were also normal on narrow-gauge lines, for obvious reasons.

When 'Atlantic' 4-4-2 engines started appearing, outside cylinders were the norm, although Mr Aspinall's famous 'Highflyers' for the Lancashire & Yorkshire had inside cylinders.

And there was one important British main line railway which had a total of five inside-cylinder engines (all tank engines, by the way) in its total locomotive stock until a new Locomotive Superintendent took over in 1896. Then inside-cylinder types began to become common on the line, or, at least, parts of it.  Any idea which railway?

*

Although few 'N' gauge modellers will model inside cylinders, many of us will mention them.  Which made me think that we had jolly well see them.  Not easy, because like a Victorian lady, inside-cylinder locomotives keep their interesting bits well-hidden.  Still, here's a coarse picturingham I made from an old illustration in my non-collection:


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-020125160815.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148177)


The fine chaps are have such fun taking this 0-6-0ST to bits.  The boiler is off, as is the buffer beam, which allows us a SuperSpiffing view of the cylinders with their covers removed.

The left-hand (Viewed facing forward from the footplate) piston can be seen, right at the end of its stroke.  Just look at that nut securing the piston rod - Mr Whitworth's finest.

The right-hand piston cannot be seen.  Unless the chaps have removed it, I assume it's in the cylinder, half-way down.  Please ignore the space between the cylinders - that's for thinking about later.

*

Now for the tricky bit of explanation.  And I'm going to be brave and slip in a bit of modellers' jargon as well.

Why's the right-hand piston half way down the cylinder and not at the opposite end?

Well, if the pistons were at opposing ends of the cylinders, the chance of the locomotive stopping in a 'blind spot', with both pistons on dead centre, would be high.  The cranks on the locomotive would be set at 180^o and, if the engine was in a good state of repair, one would only hear two exhaust beats per revolution of the driving wheels.  How peculiar.

By setting the cranks at 90^o to each other, the pistons are never at opposite ends of the cylinders and starting is more-or-less assured.  And one gets that lovely 'four beats to the bar' exhaust note - 'Wuff, Wuff, Wuff, Wuff'.  If a 'Black Five' is working a special train down the partly-reopened Waverley Route, it passes within hearing (not in sight, though) of Poppingham Towers and the sound is mightily impressive.  You see, the engine is on the climb to Falahill Summit and the regulator is up in the cab roof.

Note - we are discussing two-cylinder locomotives here.  Others to follow, later.

If the locomotive's cranks are set at 90^o (giving four exhaust beats per revolution of the driving wheels) that's quarter of a circle, isn't it?

If you ever find yourself struggling with the 'quartering' of a model locomotive, you can reassure yourself it's all in a good cause - blind spots, prevention of.

*

Did that make any sense at all?  Probably not.

Next time I'm going to attempt to let you see what the inside of a cylinder looks like.  This will involve us all taking a virtual trip to Yorkshire.


'N' Gauge is Such Fun - but, maybe, not the wheel quartering!

Many thanks for looking and all best wishes.

Cheerie-bye

John

PS Sorry about that 'Wuff, Wuff, Wuff, Wuff' bit - something of a low point I fear.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 47


Hello Chums

From Boring to Grosmont

One of the developments which enabled James Watt to make his improvements to the steam engine was boring.  You see, the cylinders for Newcomen engines were made by chaps who were, effectively, blacksmiths and, although skilled craftsmen, they struggled to obtain a suitably smooth finish to the cylinder bore.

Then James Watt became aware of the precision boring techniques for cannon which had been invented by John Wilkinson at his ironworks near Wrexham.  This permitted Mr Watt to have a much more accurate piston/cylinder interface in his engines and represents an important step which allowed for the development of the steam locomotive. 

*

Skipping elegantly over a few matters to which I'll attempt to remember to return, let's have a quick think about a steam locomotive's cylinders.  Remember we mentioned the piston is double-acting?  That means live steam has to be admitted to each end of the cylinder and exhaust steam allowed to escape, also from both ends.  This is done by having holes in the cylinder bore, at each end, called 'ports'.

Time, now, for our visit to Yorkshire, always a pleasure:-




About 1 minute 30 seconds is the bit of special interest to us.  Cylinder boring technology has moved on since James Watt's day, of course.  As one watches the film, the steam ports at the end of the cylinder are obvious.

You will notice, on the part of the bore awaiting machining, there is noticeable scoring.  This is a consequence of wear accumulated over time.  There was, for a while, a notion that wear could be reduced by having a rod at the front of the piston as well.  This passed through a bearing surface on the front cylinder cover and was covered by something a bit like a giant cigar tube.  The LSWR and NER seemed to have been especially disposed to these fitments, called 'tail rods' for a while.

The case in favour is reduced wear of the cylinder bore.  The case against is more weight, increased reciprocating masses and more bearing surfaces to keep steam-tight.  Like so many other gadgets designers tried over the years, tail rods were, eventually, abandoned as British steam locomotive design became more the pursuit of compromise than the pursuit of perfection.

*

If you enjoyed the film, here's another one featuring a '9F', from 45 seconds.  I enjoyed the bit, later in the film, with a keen chap oiling the newly-machined cylinder using a paintbrush.  I use an ever-so-slightly smaller paintbrush when oiling my Union Mills locomotives for the Table-Top Railway.  It's nice to be prototypical:-




There's only so much excitement one can take in a part of this mini-series, so, with special thanks to the Locomotive Department of the North Yorkshire Moors Railway, I'll say:


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Cheerie-B

John

And as we are still, just, in the festive period, good to see the chap in the  first clip wearing a santa hat. :D

I am learning so much from this series; really interesting and an ideal amount of information to take in on each post. Thank you!
Cheers :beers:

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 48


Hello Chums

An Initial Think about Valves

The previous 47 parts of this mini-series (47 - I originally intended a handful) have taken us to where we have a locomotive with its boiler producing live steam and cylinders - with double acting pistons, remember - all ready to go.  The first stage of getting the steam from the boiler is through the regulator.  This is a handle, big in some locomotive types and smaller in others, which the driver uses, by turning or pulling out (lots of variations exist, of course) to open the regulator valve and allow live steam to make its way to the cylinders.

It is important for the live steam for the regulator valve to be collected where the steam is driest, to avoid admitting water to the cylinders.  You know how many locomotives have a rather attractive feature atop the boiler?  With older locomotives it's usually bigger and in later locomotives it tends to be smaller, as the boiler diameter increased over time but the loading gauge normally didn't.  Once the decorative cover is removed it looks somewhat less attractive.  Its purpose is functional - the hottest steam in the boiler rises into a collector in the dome and is fed to the regulator valve, connected to the regulator handle.


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-060125172908.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148312)

[Not much elegance about this - a steam dome without a fancy cover.]


Some locomotive engineers didn't care for a steam dome and used a perforated pipe instead to collect the live steam.  These types are less common and are called 'domeless boilers'.  Boilers with steam domes are generally called 'boilers'.  Yes, an unforgiveable simplification, but it serves to show what was considered 'standard practice'. 

The Stirling family, Patrick, James and Matthew, and their close associate, Hugh Smellie, were particular enthusiasts for domeless boilers.  Interestingly, when they were succeeded by another engineer, he generally introduced steam domes - often large and elegant.  Messrs Ivatt the Elder on the Great Northern, Manson on the G&SWR and, especially, Wainwright on the SECR are good examples of this.

The GWR was interesting (isn't it always?).  Mr Dean favoured large domes and Mr Churchward's carefully designed and magnificently constructed standard boilers were  were domeless.  But the GWR had a legacy of pre-Churchwardian types, many built after the great man's retirement, with magnificently-domed boilers.  Just think of all these pannier tanks.  Mr Hawksworth eventually introduced pannier tank designs with domeless boilers.


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-060125172355.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148311)

[Steam domes come in various sizes.  0-6-0PT No. 5764 has one of what might, politely, be called Jane Russell proportions.]

*

Having got the regulator and steam dome, or absence of one, out of the way.  Let's think what happens to the live steam when the driver cracks open the regular handle.  It flows through pipes towards the cylinders.  Please note, the locomotive in my mind's eye is not superheated.

But here's a thing.  Remember, unlike a typical internal combustion engine, a steam engine is double-acting.  We saw the steam ports at each end of the locomotive cylinders in those splendid films from Grosmont.

Can you see the problem we face?  We have to be able to admit live steam to each end of the cylinder (at different times or we'll be going nowhere!) and we have to allow the exhaust steam to leave the cylinder and make its way to the chimney.  Keeping live steam and exhaust steam separate is essential - we don't want our precious live steam escaping before it does any work.

For many years, from the Stephensons' time until almost the superheater era, (with a few interesting exceptions) this was achieved by using 'slide valves'.  Put simply, a rectangular piece of metal with three square-ish holes cut in it.  Some sort of mechanical contraption - we'll think about these later - moves the valve to-and-fro within the 'valve chest', which also has holes cut in it.  The whole thing is so constructed as to allow the holes in the valves and the valve chest to coincide when we want them to.

This allows live steam into the cylinder, at either end, and the exhaust steam to escape when we want it to - all achieved by making these holes line up at the correct time..  To achieve separation, with slide valves, the two holes at each end of the rectangular valve are normally used for live steam and the hole in the centre for exhaust steam.  The construction of the valve chest then keeps the exhaust steam separate from the live steam.

Typically, a slide valve will have a movement of 3in - 4in, which allows for all the necessary covering and uncovering of the holes to take place.

I hope this made some sort of sense.  The important thing to remember is a double-acting steam engine needs to admit and remove steam from each end of a cylinder.  The slide valves allow this to happen.  For us 'N' gauge modellers, unless interested in particularly unusual prototypes, all this is of academic interest as, due to the aforesaid 'mechanical contraption', which moves the valves, generally being between the frames in the slide valve era, the valve chest is there as well.


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-060125172040.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148310)


Back to the picturingham of the semi-dismantled 0-6-0ST.  That space in the cylinder block, between the cylinders, is the valve chest.  Incidentally, the arrangement of inside cylinders with a common steam chest between them, as seen in the picturingham,  was patented by Robert Stephenson & Co, in 1841.  Although I consider this short mini-series as entertainment, rather than educational, I'd be super chuffed if anyone reading it comes away with a better appreciation of the contribution to the development of the steam locomotive made by that remarkable man, Robert Stephenson.

We met him last on a quayside in Columbia (sounds like the title of a paperback 'thriller') giving a broke Richard Trevithick his fare home.  Now, a few years later, his firm patents what became pretty much the most common cylinder and valve chest arrangement used in Britain for over 50 years.  And, in some cases, longer than that.

Let's restrict ourselves to British standard-gauge mainline railways.  The final class built with slide valves?  I believe this to be our old friend the GWR '9400' class 0-6-0PT, built from 1947-1956.  Another class worth special mention  is the 1949-1951 batch of 'J72' 0-6-0T engines - a NER design going back to 1898. A century after Robert Stephenson's patent, the arrangement was still being used for new construction.

Unless one manages to become intimately involved with steam locomotive maintenance, it's unlikely we'll see much evidence of slide valves in British practice.  However, Linda, on the Ffestiniog Railway, has slide valve chests on top of her outside cylinders.  Her sister, Blanche, is different.  Have a look, if you like, at pictures of the two engines and you'll see what I mean.

Now, I've been a cheeky chappie and suggested slide valves were generally replaced by a different arrangement.  We'll come to this in a later part.

*

A quick question, if I may, for any of the proper enginemen who have endured reading this.  Have you encountered the technique of closing the regulator before moving the reverser on an engine with slide valves?  The idea being to take the pressure off the valve faces.  I'd be keen to know.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

Though I'm very familiar with the mechanics of the steam loco, this is a brilliant explanation for a layman to follow.

Well done again, John!

Martyn

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 49


Hello Chums

Some More about Valves and then Back to Cylinders

In part 48 of this brief mini-series we attempted to look at slide valves.  Not an easy thing to do as that great engineer, Robert Stephenson, worked out that the best place to put them on an inside-cylinder locomotive is between the cylinders.

And, as we have seen, British locomotive engineers tended to enjoy inside cylinders.  They especially liked placing the 'mechanical contraption', which moves the valves, between the frames.  Makes it much less accessible for enginemen 'oiling up', fitters fitting and, of course, less disturbing for members of the public of a nervous disposition to see in action. 

*

From early times there was a notion that a different type of valve from the slide valve, more like a mini-piston, or, to be exact, a pair of mini-pistons on a stick, might be a good idea.  The first example of a locomotive fitted with piston valves was earlier than one might think.  1832.  Robert Stephenson & Co built Atlas, an 0-4-0, for the Liverpool & Manchester Railway.  The idea was ahead of its time - piston valves proved more difficult to keep steam-tight and the elegant simplicity of the slide valve won the day.

I'm glad to be a life member of the Vintage Carriages Trust, based at Ingrow (West) on the Keighley & Worth Valley Railway.  The Trust has three locomotives in its collection.  Of these, Bellerophon, an 0-6-0WT, was one of six similar locomotives built for the Haydock Collieries. Bellerophon , completed in 1874, was built by the Haydock Foundry. You might have seen this little brown engine, either on the K&WVR or on the Foxfield Railway.  What might have escaped your notice is he (the Trust uses the masculine pronoun, as will I) has piston valves.  The valve chests are above the outside cylinders - a strikingly modern arrangement.

However, it wasn't until 1887 that piston valves were reintroduced for British main-line railways.  On a railway that is something of a favourite of mine - the NER.  That inventive engineer, WM Smith, Chief Draughtsman of the NER, is credited with making improvements that made piston valves a practical proposition.  We'll hear more of Mr Smith later, I expect*.

I think the exploits of Wilson Worsdell's 'R' class 4-4-0 for the NER, introduced in 1899, really showed the superiority of piston valves.  The first of the class was put onto a double-manned diagram:- Newcastle-Edinburgh-Newcastle-Leeds-Newcastle, Monday to Friday.  That's 455 miles each day.  She had an easier time of it on Saturdays with a diagram of 161 miles.  Boiler wash-out on Sundays.  This is a total of 2,436 miles each week.  At the time, it was considered that this level of performance was made possible due to the class being equipped with Mr Smith's design of piston valves.  I love an excuse to include a picturingham of a Union Mills 'R' class:-


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-080125100925.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148350)


Even allowing for the many deficiencies of my coarse photography, you might be able to discern that the 'R' is an inside-cylinder locomotive.  Yes, some traditional-looking British inside-cylinder locomotives had piston valves, hidden between the frames.  The multitude of MR/LMS '4F' 0-6-0s can certainly be called 'traditional' - here's one of the class being erected:-


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-080125150020.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148351)


One of Mr Smith's clever developments to the piston valve (can we call him SuperSmith?) was to place the valve chests above (or below) the cylinders, as can be seen in the picturingham.  This was a substantial break from the normal practice with slide valves where there was, as we have seen, a common steam chest between the cylinders. Of course, slide valves could also be arranged above or below the cylinders.

Back to Cylinders

The '4F' has 20 inch diameter cylinders.  As the picturingham shows, the space between a locomotive's frames is limited.  We start off with a gauge of 4 ft 8 1/2 in., take off a bit for the width of the frames, then another bit for the clearance between the wheels and the frames. The flange roots of the wheels cannot be hard against the inside face of the rails, so we need to add another bit of clearance to allow for the 'coning' of the wheel tyres to be effective.  All these bits add up and act to restrict the distance between the frames.

Which means the space between the frames is a constraint on the diameter of the cylinders of an inside-cylinder locomotive.  I had an agreeable time looking through some books and the largest diameter of inside cylinders I can find is 20 in., like on the '4F' seen in the picturingham or the powerful GER 0-6-0s later known as class 'J20'.  There are others, but I cannot find an example with cylinders over 20 in diameter.  Do you know of one?

I propose to take a break from valves for a while and return to cylinders in the next part.  There are some matters we might like to consider.  We'll then return to piston valves.

*Incidentally, Mr Smith was on good terms with SW Johnson, Locomotive Superintendent of the Midland Railway.  Mr Johnson was persuaded regarding the benefits of piston valves and, from 1893, fitted them to some of his express passenger locomotives.  Particularly noteworthy was their fitting to the later batches of his SuperSpeedy 4-2-2 'Spinners'.


'N' Gauge is Such Fun

Many thanks for looking and all best wishes.

Tickety-tonk

John

The ex GCR Sir Sam Fay class, LNER B2, initially had 21.5 " inside cylinders, but at least some of the class had them later lined up. If you Google the class, one of the links (LNER encyclopedia) also mentions something also alluded to in this series, poorly designed steam passages.

Martyn

Incidentally, the J20s were effectively an 060 version of the B12, with the same cylinders. The GER had done something similar with the J19s using the Claud boiler and cylinders, but in the latter, the boiler pressure was reduced to 160lb: the J20 retained the 180 lb of the B12s.

Martyn

Thank you very much, Martyn.  That is interesting about the 'Sir Sam Fay' class.  I knew these were impressive-looking engines but with disappointing performance. After reading the article you suggested, I can see why.  I noted with interest that the massive inside cylinders resulted in axlebox width being compromised.

Mr Robinson was not alone in having difficulty going from the 4-4-0 to the 4-6-0.

I'm always particularly grateful for contributions like this to the discussion.  And the cylinder diameter mentioned will make for an interesting point of comparison in the next part in the mini-series.

Thanks again and all good wishes.

John

Thank you, John, wonderfully educational and informative as ever. I've often thought that steam locomotives are examples of the way technology advances by gradual development, trial and error until it reaches the limits of what further development can achieve and is then superseded by a different technology altogether. The internal combustion engine appears to be reaching the same point.

Quote from: Train Waiting on January 06, 2025, 10:08:33 PMThe previous 47 parts of this mini-series (47 - I originally intended a handful)

You have obviously taken the idea of Douglas Adams' Hitchhiker's Guide to the Galaxy, a Trilogy in five parts, and expanded it further! Looking forward to the next 48 parts.

Cheers,

Chris

Quote from: Train Waiting on January 08, 2025, 06:16:14 PMBack to Cylinders

The '4F' has 20 inch diameter cylinders.  As the picturingham shows, the space between a locomotive's frames is limited.  We start off with a gauge of 4 ft 8 1/2 in., take off a bit for the width of the frames, then another bit for the clearance between the wheels and the frames. The flange roots of the wheels cannot be hard against the inside face of the rails, so we need to add another bit of clearance to allow for the 'coning' of the wheel tyres to be effective.  All these bits add up and act to restrict the distance between the frames.

Which means the space between the frames is a constraint on the diameter of the cylinders of an inside-cylinder locomotive.  I had an agreeable time looking through some books and the largest diameter of inside cylinders I can find is 20 in., like on the '4F' seen in the picturingham or the powerful GER 0-6-0s later known as class 'J20'.  There are others, but I cannot find an example with cylinders over 20 in diameter.  Do you know of one?

So Brunel was right, and we should have gone with broad gauge?

No-you change to outside cylinders (or multi cylinders), and change the loading gauge!  :D  :D

Just look at the size of some of the US and Canadian locos. ;)

Martyn

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 50


Hello Chums

Back to Cylinders

'At the end of 1897 there was no British locomotive superintendent designing two-cylinder non-compound engines with outside cylinders, other than small shunting locomotives. In 1898 Ivatt's GNR 'Atlantic' engine appeared and since then the use of outside cylinders has greatly increased.'*

I mentioned earlier that, although the inside-cylinder type became predominant after Robert Stephenson's Planet, outside-cylinder locomotives continued to find favour on certain British railways. You might recall this from part 46 of this brief mini-series:

'And there was one important British main line railway which had a total of five inside-cylinder engines (all tank engines, by the way) in its total locomotive stock until a new Locomotive Superintendent took over in 1896. Then inside-cylinder types began to become common on the line, or, at least, parts of it.  Any idea which railway?'

Profuse apologies for quoting myself - the last refuge of the pub bore.  By the way, the answer is the Highland Railway.

But, by the early 'Nineties, the two cylinder locomotive with outside cylinders appeared to be reaching the end of its time in Great Britain.  Elsewhere, outside cylinders were very much the norm.  Inside-cylinder types could be seen (The Netherlands and Portugal being examples) but they were in a minority world-wide.

Then along came Mr Ivatt the Elder with his first 'Atlantic', No. 990, happily still with us, which was the heaviest locomotive in Great Britain at the time of its introduction in 1898. 


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-090125190640.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148388)


No. 990 was the first British express passenger tender locomotive to run on five axles.  The previous tender engines with 10 wheels, David Jones' 4-6-0 locomotives of 1894 for the Highland Railway and William Dean's experimental Great Western 4-6-0, No. 36, of 1896, were for goods traffic.

The era of the Big Engine had arrived, just in time for the new century and the greatly increased train weights it would bring.  We discussed the increase in size of locomotives and their increasing number of wheels in the first section, so there is no need to repeat that here.  But it helps us to be aware that, to cope with changing operating conditions, locomotives were getting bigger and beginning to 'outgrow' the traditional 4-4-0 and, to a lesser extent, 0-6-0  types.

A consequence of this enlargement of the steam locomotive was the potential constraint placed upon the designer by inside cylinders.  I was grateful @martyn drew our attention to the 21 1/2 inch diameter inside cylinders of the Great Central's 'Sir Sam Fay' class.  These managed to fit between the frames although there mustn't have been much space left, but the proximity to the frames of the cranks led to insufficient bearing surfaces on the driving axleboxes.

However, 20 inch diameter inside cylinders were used on several very satisfactory classes, including the 'B12' 4-6-0, with its 20 inch bore by 28 inch stroke cylinders.  Incidentally, I'm not aware of any locomotives having inside cylinders with a stroke longer than 28 inches.  Can you think of any?


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-090125182545.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148386)

[A 'B12' 4-6-0, this example is of the LNER rebuild as 'B12/3'.  I think it is fair to say this was the most successful 4-6-0 class with inside cylinders. An attractive engine as well.]

*

There then began a gradual - but so very gradual - move away from inside cylinders.  The various two cylinder 'Altlantic' designs following Mr Ivatt's No. 990 had, with the exception of Mr (later, Sir John) Aspinall's 'Highflyers' for the L&YR,  outside cylinders.  The final North British 'Atlantics' had 21" x 28" outside cylinders.

Although all but one of the locomotive engineers, who tried the type, settled for outside-cylinder 'Atlantics', the situation regarding 4-6-0s was more complicated, with a variety of inside-cylinder and outside-cylinder types being introduced, sometimes on the same railway.

Between 1902 and 1921, JG Robinson designed nine, yes nine, 4-6-0 types for the Great Central.  Two were four-cylinder engines and are not for our notice at present. Of the remaining seven types, five had their cylinders outside and two inside.

On the Caledonian, between 1902 and 1922, Mr McIntosh introduced five types of 4-6-0 with inside cylinders of up to 21" x 26" size and his successor, W Pickersgill produced two types of 4-6-0 with outside cylinders.  And a three-cylinder 4-6-0 class of extraordinary incompetence.

For smaller locomotives, two outside cylinders were unusual for designs introduced after 1900 - the GWR 'County' 4-4-0s, and the Highland Railway's Snaigow and Durn being interesting examples.

* 

At this point the problem of the British loading gauge presents itself.  There are several aspects to this, but the one of relevance here is that caused by the British love of station platforms.  Platform clearance is critical for locomotives with outside cylinders and, of course, each of the pre-Grouping companies set its own standard.

21 inch diameter outside cylinders can be found on other classes, such as the LSWR 'H15' class 4-6-0 (21" x 28") and the LBSCR 'K' class 2-6-0 (21" x 26").  Especially, they can be seen on the LMS 'Horwich Mogul' 2-6-0 class (21" x 26"), but set high and at a sharp angle in order to provide platform clearance on the 'tighter' parts of the LMS system. This class demonstrated it was more difficult for the 'Big Four' companies, or, at least, three of them, as they had to contend with the differing loading gauge dimensions of their constituents.  Easier, of course, for the GWR.


(https://www.ngaugeforum.co.uk/SMFN/gallery/148/6222-090125182619.jpeg) (https://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view&id=148387)

[In order to prevent the 21 inch diameter cylinders bashing into station platforms, Horwich Drawing Office raised them high, which then required a sharp angle to get the connecting rod to meet the crankpin.  I've always thought these 'Horwich Moguls' were attractive engines.  Good performers too - they could steam, had plenty of power and good brakes.  Sir Henry Fowler got his hands on the design after Mr Hughes retired and 'Midlandised' some of their details, including equipping the class with that ridiculously narrow Midland tender.]


I think the largest diameter outside cylinders used in Great Britain were on a couple of Mr Urie's designs for the LSWR - the 'N15' 4-6-0, later called the 'King Arthur' class, with 22" x 28" cylinders and the LSWR 'G16' class 4-8-0T shunting engines, also with 22' x 28" cylinders.  Mr Maunsell arranged for all but one of the 'N15s' to have their cylinders linered down to 20 1/2" in the course of general repairs during 1927-1929.  No. 755, The Red Knight, continued to run with 22 inch cylinders until withdrawal in 1957.  Apparently, there was no appreciable performance advantage to No. 755's larger cylinders.

*

In the next part, I'm hoping to draw some of the threads together and I'm going to attempt an approach that I've never seen before.  Of course, it will have been done, but I've not seen it.

* EL Ahrons, The British Steam Locomotive 1825-1925, Locomotive Publishing Company, London, 1927, Page 311.


'N' Gauge is Such Fun

Many thanks for looking and all best wishes.

Cheerio

John

John

I've got a question for you that you don't need to answer if it at all derails your thread. In the last photo of the model 4-6-0, we see the centre drivers being closer to the front drivers than the rear ones; that is, they are not quite in the middle. It seems to me that there are many 4-6-0s that share this asymmetry such as the various class 5 locos. Yet, in Pacific wheeled locos, the middle drivers are usually right in the middle.

Webbo

@Webbo I think this was done to get even weight distribution on the three driving axles while on Pacifics this could be achieved by the distance of the trailing axle.

So, outside cylinders were only avoided in Britain because of the loading gauge?
Are there any other advantages of having inside cylinders? I ask as I always feel that locomotives without a connecting rod are missing something ...

I am more used to German types, and especially the northern Germans avoided inside cylinders like the plague (like Robert Garbe of the Prussian State Railways with his P8, when only after his retirement a much needed 3-cylinder P10 could be built), or later Richard Paul Wagner of the Reichsbahn who made trials between 2- and 3-cylinder types (BR 43/44) where the 2-cylinders always won with the only reason of being cheaper to build and run.
Only later when the 2-cylinder BR 43 really needed to show that they could perform just as well and failed miserably, were the BR 44 built for heavy goods trains.

Inside cylinders were avoided because maintenance was more difficult, and the complicated to manufacture "Kropfachsen" (sorry, I didn't find the English term for this) were seen as a weak spot instead of the straight axles for two outside cylinders.

"Kropfachse" of a German BR 44 3-cylinder:

(https://hellertal.startbilder.de/1200/treibachse-kropfachse-schweren-gueterzug-dampflokomotive-baureihe-374667.jpg)
© Armin Schwarz, from https://hellertal.startbilder.de/bild/deutschland~bahnhoefe-in-rheinland-pfalz~betzdorfsieg/374667/treibachse-kropfachse-einer-schweren-gueterzug-dampflokomotive-der.html


In southern Germany (Bavaria, Baden, Württemberg), inside cylinders were more common – but only with 3- and 4-cylinder locomotives. 2-cylinders were also mostly built with outside cylinders.

One reason for the unequal wheelbase in 460s, and 060s, was because of the position of the firebox.

This generally fitted more or less between the middle and trailing wheels, or if sloping firebars, above the trailing and then down to the ashpan.

On a pacific, or anything else with a trailing bogie or pony trick, the firebox was supported above it.

I think...

@Hiawatha

Crank axle.

Not sure why the British continued with inside cylinders for so long. Maybe it was the desire to look tidy, and not have things like pipework and auxiliaries on view. Without going through books, there were a number of accidents caused by the crank axle failing in service.

But simplicity and ease of maintainence became keynotes as labour for keeping locos running became in shorter supply, and presumably also because of time taken to access and oil inside gear. Hence the change to outside cylinders.

It may be the racking forces of outside cylinders which lead to the use of inside. With inside, the piston thrust was close to the centre line of the chassis, but with outside, the thrust was further from the centre line causing frames to flex if not sufficiently braced. The inside cylinder steam chest could be used as part of the bracing at the front, whereas, I think, the outside couldn't.

Martyn

** I've deleted an incorrect reference to the B12s

Martyn