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




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.





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.




[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

  

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 

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.





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.





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! 





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.




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:





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