The RCTS history of the Duke tells a different story of the ashpan.

In late 1961, the Crewe North shedmaster instructed the shed to cut extra slots in the ashpan to improve airflow. This improved things, but too little too late.

In preservation, it notes that it was found necessary to replace the original ashpan. With no drawings available, a copy was made of the original. But just as this was completed, the original drawings were found, and it was discovered that the ashpan damper door air space was 72 sq in too small in the original one. The new ashpan was modified to this new, (correct?), arrangement.

The blastpipe and draughting arrangements were modified to Kylchap at the same time; trials were carried out to optimise the exhaust dimensions.

It was found on trials, if I've understood the text correctly, that these combined alterations improved the boiler steaming capacity by around 40-50%. The loco also has had modification to the cams, which combined with other detail changes, has transformed the loco's performance on the road. Trials had shown in BR days that the valve gear gave a better, more efficient, cylinder performance than piston valve types.

As an aside, tables within this loco's history seem to show up what has been said before in this thread; that though the King class could produce cylinder horsepower of around 2000, the drawbar hp was about 1190. Was this loss of power due to the 'internal resistance' mentioned earlier? It also shows that the Duke had a power output similar to, or slightly above, that of a Duchess when on trials, and post preservation runs have shown the loco capable of 'extremely high' drawbar horsepower, close to the maximum recorded in the UK (which, I think, was a short lived 3,300hp by a Duchess).

Martyn

 

 

Quote from: martyn on March 03, 2025, 10:45:48 AMclose to the maximum recorded in the UK (which, I think, was a short lived 3,300hp by a Duchess.

Yep - 6234 Duchess of Abercorn, 26th February 1939, on a test run with a 20-coach train (including a dynamometer car) after having a double chimney and blastpipe fitted.
This was a repeat test, following one a few weeks before which showed that the locomotive's power was compromised by its single blastpipe.

Drawbar horsepower on the second test was frequently over 2,000 hp (1,500 kW) and a maximum of 2,511 hp (1,872 kW) was recorded.
The horsepower at the cylinders could only be estimated; Cecil J. Allen thought it to be 3,333 hp whilst O. S. Nock was more conservative at 3,209 hp.
This could not be expected on day-to-day workings as it required two firemen to shovel the coal, one couldn't have done it.

Following this test, all subsequent new build Coronations were given a double chimney and blastpipe, whilst all those already in service had them retro-fitted during overhauls - the last to be converted being 6220 Coronation in 1944.

BR performed a similar test some seventeen years later, using 46225 Duchess of Gloucester, which established that a continuous drawbar horsepower of 2,000 hp was readily sustainable.

when the Duke came to Didcot, it was to enable it to be tested by BR as it was the first Caprotti locomotive on BR metals since the end of steam. it is many years since this happened so please excuse my inability to remember which year the following happened. the Duke was to do a loaded test of I believe 10 coaches plus the ex Western Region Hawksworth dynamometer car the the Duke group owned, to run between Derby and Sheffield (to this day I cannot remember which direction!) the net result of this was that the Duke managed this in a time that was only 5 minutes outside HST timings for that route! the chief engineer at the time Gary Shannon later asked me on a day that I was driving it at Didcot to run the water down to one third of a glass but keep as much pressure as possible after coming off the demonstration line so that he could test the rate that the injectors were working at, as it seemed that on the test run it was getting through a lot of water, and both injectors had needed to be employed to maintain the water level. I cannot remember now what was decided, but they were thinking of increasing the cone size on one of the injectors.
the picture below is a very happy Hailstone about to leave that shed



Despite being labelled a Western man, I love Standards!

Regards,

Alex

John,

Catching up here after a few busy days and unable to check in.

Firstly, hope all has/is going well at hospital.

And secondly, as always fascinating info - I am learning so much from this thread which makes for such a pleasant from focus on a work on a "desk day", when I stop for morning coffee (since in this time zone your updates arrive perfectly as "morning reads" - worst case being, if there are interrupts, I get to it by elevenses... ),

Best Wishes,

Colin   

@Hailstone


That was an honour, and it must have been a fantastic experience.

The RCTS history says that (BR trials post preservation) 'trials....showed that the steaming performance performance of the engine had been so improved that the injectors could not keep pace.....these have subsequently been uprated'

Martyn

Please forgive my naivety, but I'm wondering whether an N-Gauge no.71000 would prove a popular addition to modellers' collections - and don't tell me that it's a "one-off", rarity of a loco, and that it would never sell (it could be marketed as in its original condition and in its preserved state) - what about Bachmann/Farish's popular "Deltic" prototype and the delightful (even more popular?) ex-LMS "twins"... and to a lesser extent, the "Brighton Belle", or the (original) "Midland Pullman"..?

Rant now over! Phew!

Quote from: Cols on March 05, 2025, 12:51:57 PMPlease forgive my naivety, but I'm wondering whether an N-Gauge no.71000 would prove a popular addition to modellers' collections - and don't tell me that it's a "one-off", rarity of a loco, and that it would never sell (it could be marketed as in its original condition and in its preserved state) - what about Bachmann/Farish's popular "Deltic" prototype and the delightful (even more popular?) ex-LMS "twins"... and to a lesser extent, the "Brighton Belle", or the (original) "Midland Pullman"..?

Rant now over! Phew!

I for one would be interested, and I don't have any tender engines on my layout.

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 73


Hello Chums

More Than Two Cylinders - 1

As I've mentioned before, part of the fun of trying to write this super-brief mini-series is using an approach that attempts to consider aspects of the steam locomotive in isolation. Doomed to failure! We are now going to discuss locomotives with more than two cylinders, but I have found myself having little option but to mention these in passing before. However, this is where we consider the matter in some detail.

We have a difficulty before we even get started. Compound locomotives! With your permission, we'll ignore these at present and consider only non-compound engines - known as 'simple expansion' or 'simple' locomotives. We'll return to compounding later and a volunteer to write the postington/s is being actively sought. Bribery can be arranged.

**

From the time the 'steam dinosaurs' were established, through the emergence of the classic 'Stephensonian' locomotive with Rocket, Northumbrian and Planet, to the dawn of the Era of the Big Engine, steam locomotives normally had two cylinders. In British practice, usually but by no means exclusively, inside.

My use of 'normally' is intentional.  Simple-expansion locomotives with more than two cylinders might go back a tad further than you think. By the way, from now on I'll dispense with the term 'simple-expansion' - please assume that's the type of locomotives we are discussing unless mentioned otherwise.

How far back?

1846! Robert Stephenson & Co. constructed one of a type of 4-2-2 locomotive it was building for the LNWR as a three cylinder engine.  It ran a successful trial in April 1847; Wolverton to Coventry - 41 miles - in 42 minutes. However the LNWR preferred two-cylinder engines and, 1853, the locomotive was rebuilt as a three-cylinder 2-2-2 for the York, Newcastle & Berwick Railway.





I haven't been able to find an illustration of the three-cylinder locomotive, which was the subject of Stephenson and Howe's patent of 1846, but the picturingham shows a drawing of one of the similar two-cylinder locomotives.  Incidentally, we met Mr Howe earlier as he was one of the inventors of the Williams-Howe link motion in 1842, normally called Stephenson link motion after the firm.

The next three-cylinder engine appeared in 1868, an 0-6-0 goods locomotive for the Blyth & Tyne Railway.

It took rather a long time before another three-cylinder locomotive for use on British railways appeared. Any idea what it was?





Yes, James Holden's 0-10-0WT 'Decapod' of 1902 for the Great Eastern, which was rebuilt as an 0-8-0 two-cylinder tender engine in 1906. The next three three-cylinder locomotive types were, like 'Decapod', tank engines.

John Robinson's 0-8-4T hump shunting engines of 1907 for the Great Central were next to appear.





Now, our attention turns to the North Eastern, with Wilson Worsdell's 4-8-0T of 1909* for heavy shunting and Vincent (later, Sir Vincent) Raven's 4-6-2T class of 1910 for heavy mineral traffic.







In the next part we'll discuss the re-emergence of three-cylinder tender locomotives. Any ideas what was next after the Blyth & Tyne 0-6-0?

Finally, a look furth of Great Britain.

There were experimental three-cylinder locomotives in the USA in 1847/48. The Wyoming Valley Railway later tried the concept on a few types, including 4-4-0 passenger engines.

In Germany, some three-cylinder 0-6-2T locomotives were built in 1902 for local traffic in the Berlin area.


* The last new locomotives to be built at Gateshead Works. Construction then moved to the NER's new works at Darlington.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

John
41 Miles from Wolverton

http://www.railwaycodes.org.uk/elrs/_mileages/l/lec1.shtm

London Rugby

http://www.railwaycodes.org.uk/elrs/_mileages/r/rbs1.shtm
To Coventry

41 Miles 46 chains
Pretty good going back in those days

A Coarse Guide to the Steam Locomotive for 'N' Gauge Modellers - Part 74


Hello Chums

More Than Two Cylinders - 2

We ended the previous part with a question:- 'In the next part we'll discuss the re-emergence of three-cylinder tender locomotives. Any ideas what was next after the Blyth & Tyne 0-6-0?'

There were two one-off three-cylinder tender engines. Both were conversions.

In 1889, a Webb compound locomotive on the LNWR was briefly tried with the low-pressure inside cylinder reduced from 30 inch diameter to 20 inch and with high-pressure steam admitted to all three cylinders. I've not been able to find out much about this experiment. Please feel free to add more details in the discussion.

Twenty years later, Mr Robinson converted one of the Great Central's two-cylinder 'Atlantic' locomotives to three cylinders. In 1922 the locomotive reverted to the standard two-cylinder arrangement.

Having had considerable success with three-cylinder tank locomotives on the North Eastern Railway, Mr (later, Sir Vincent) Raven¹ designed, in 1911, a three-cylinder development of Mr Worsdell's successful 'V' class 'Atlantic. Darlington Works was fully committed to a building programme so, for the first time in many years, the NER placed an order with an outside builder, in this case the North British Locomotive Company in Glasgow.

But not for a single prototype - for twenty engines. Ten were saturated and 10 superheated. Unsurprisingly, the superheated ones were superior and a further 30 were built up until 1920. And what engines they were - fast, reliable and, with a reduced 'hammer blow', easier on the track and structures.




[A NER 'Z' three-cylinder 'Atlantic'. These were magnificent locomotives. Convincing proof of the value of three cylinders.]


In 1920/21, Sir Vincent arranged detailed comparative tests between the three-cylinder 'Z' class and Mr Worsdell's two-cylinder 'V' class. By then, all NER 'Atlantics' had been fitted with superheaters. Unlike some specially-arranged trials, the test results were based on the locomotives' performance in day-to-day service.

The results are interesting for those of us who are fascinated by steam locomotives as they are the best comparison between two and three-cylinder locomotives of a similar basic design.

Here's the main findings:

The 'Z' class showed a 23% reduction in coal consumption over the two-cylinder 'V' class;

Average annual mileage for the 'Z' class was 34,392 compared with 26,579 for the 'V'.

Slightly later figures, from 1924, show heavy repair intervals for the 'Z' class averaged 73,000 miles. For the 'V' class it was 58,000 miles.

Please don't think the 'Z' 'Atlantics' had an easy life - they were the front line motive power for the York-Newcastle-Edinburgh line until the Gresley 'Pacifics' took over many duties in LNER days. Even then, the 'Atlantics' continued to be used on lighter trains, such as Pullman workings.

Sir Vincent deserves recognition as the locomotive engineer who understood thoroughly the benefits of a three-cylinder engine. The most spectacular rewards for this would come after the Grouping. Meanwhile, he had turned his attention to the heavy mineral traffic. In 1913, the NER's annual mineral traffic was 59.7 million tons, the highest in the country. Next was the GWR with 47.6 million tons.

The NER eventually had 120 of the superheated 'T2' class two-cylinder 0-8-0 locomotives. Introduced in 1912, to Mr Raven's design, these were excellent engines. Sir Vincent took the design a stage further in 1919 with his 'T3' three-cylinder version. Fifteen were built and worked many of the heaviest mineral trains such as the Tyne Dock - Consett iron ore workings.

The late OS Nock wrote memorably of one of the class on one of these trains. She worked for 35 minutes on full regulator with the reverser one notch from full gear. A full glass of water was maintained (although the steep gradient would have made the water level read high) and the engine blew off just beyond Beamish. Mr Nock wrote,

'[...] it seemed as though this amazing engine could have sustained this effort indefinitely.'²

*

Time, now, to, reluctantly, drag ourselves away from the doings of the NER and see what other locomotive engineers thought of three-cylinder locomotives.

Mr Churchward had considered three-cylinder locomotives for the Great Western but did not proceed to build any. However, one of his young engineers, Harold Holcroft, took a particular interest in these. We'll hear more later about Mr Holcroft and his important contribution to three-cylinder locomotives.

Mr (later, Sir Nigel) Gresley, Chief Mechanical Engineer of the Great Northern, became absolutely convinced of the value of three-cylinder locomotives and built some for the Great Northern and many, many more for the LNER. His Great Northern designs comprised 2-6-0, 2-8-0 and 4-6-2 wheel arrangements. Like Sir Vincent Raven earlier, Mr Gresley was a total convert to three-cylinders for medium-sized and large locomotives. We'll discuss the Gresley locomotives in some more detail later.

In the south, Mr Maunsell had three-cylinder versions of his 'N' and 'U' 2-6-0s for the SECR and the the Southern. One of his ill-fated 'River' class 2-6-4T locomotives, No. A890 River Frome was built with three cylinders. The eight 0-8-0T shunting engines of class 'Z' also had three cylinders, as did the 'W' class 2-6-4T goods tank engines.

Mr Maunsell's most successful three-cylinder design and, arguably, his most successful locomotive class, was the 'Schools' 4-4-0 of 1930. We'll probably discuss this class in more detail later.

Once OVS Bulleid was appointed as Mr Maunsell's successor, the Southern embarked upon an enormous building programme of his innovative three-cylinder 'Merchant Navy', 'West Country' and 'Battle of Britain' 4-6-2 locomotives.

Lastly, to the LMS.

I think the only three-cylinder simple expansion locomotives the LMS inherited from its constituent companies were the four members of the Caledonian Railway's '956' Class, designed by William Pickersgill and introduced in 1921. This was a design of legendary incompetence and it's difficult to think of a worse locomotive. Mercifully, no more were built and they didn't influence the design of any other classes. The LMS scrapped all four as soon as it decently could.




[Massive and useless. A Caledonian '956' three-cylinder 4-6-0, seen here at Perth. The largest locomotives built for a Scottish railway. Probably the worst as well.]


It's fair to say that the locomotive affairs of the LMS were not altogether satisfactory from the time of Mr Hughes' retirement as Chief Mechanical Engineer in 1925 until the appointment of Mr (later, Sir William) Stanier in 1932. The goings-on during that period would make a mini-series in their own right. However, the successful three-cylinder 4-6-0 'Royal Scot' class appeared in 1927, followed by the nominal rebuilding of two ex-LNWR four-cylinder 'Claughton' 4-6-0s as the first of the three-cylinder 'Patriot' class. Subsequent members of the class were new engines.

Mr Stanier carried on construction of three-cylinder locomotives with his '5XP' or 'Jubilee' class of 1934. These were, effectively, taper boiler versions of the 'Patriots'. This was the most numerous class of three-cylinder locomotive in Great Britain but their introduction was marred with several problems, one of which was due to Mr Stanier's unfamiliarity with three-cylinder locomotives.




[A Stanier '5X' or 'Jubilee' three-cylinder 4-6-0. Britain's most numerous class of three-cylinder locomotives. Many early teething troubles which were eventually, more-or-less, overcome. The model is by Rivarossi for Peco. Has there ever been a better British-outline locomotive in 'N' gauge?]


Mr Stanier designed one other class of three-cylinder locomotive for the LMS, the '2500' class of 2-6-4T for former London Tilbury & Southend Railway's lines. A total of 37 were built, entering service in 1934. Fortunately, one has been preserved and is in the National Collection.

I think that concludes our introduction to three-cylinder locomotives. The next part will provide an overview of four-cylinder types, then we'll discuss some of the technical matters regarding locomotives with more than two cylinders. The most important of which is, 'why bother?'


¹ Knighted in 1917. The then Mr Raven had been seconded to war work for HM Government in 1915, rising to Controller of Armament Production for the Admiralty.

² OS Nock, LNER Steam, David & Charles, Newton Abbot, 1969, page 214.


'N' Gauge is Such Fun!

Many thanks for looking and all best wishes.

Toodle-oo

John

Excellent, John.

And to answer your question about the Peco locomotive, no.

Again, thanks John, and welcome back.

Just a short piece about the NER T3/LNER Q7 from the RCTS book.

Basically, it questions why the T3s were actually built! The T2/Q6 were more than powerful enough for the traffic handled, and the book conjects that it was an exercise by the Drawing Office/Locomotive Superintendent to see just what power could be easily obtained by three cylinder superheated goods locos.

In trials on Glenfarg bank, (in Scotland, for the benefit of the NBR), the T3 took 755 tons up the bank; the GWR 28xx 2804 could only manage 591 tons, having not been able to take 683 tons (in poor weather).

Looking forward once again to the next parts.

Martyn

Welcome back to the NGF and your wonderful mini-series, although now it really is not a 'mini' series; worthy of a proper book I reckon. As to your question regarding the Peco/Rivarossi 5XP, then the only one I would propose is a Castle class. I have the Peco 5XP with a coreless and DCC conversion of my own design, it runs very well and does not look at all out of place with the modern locos on the club layout at exhibitions.
Looking forward to the next instalment!
Cheers!

Thanks for the quote from Ossie Nock's book 'LNER steam', John.

This was one of the first railway books which I bought, and I may even still have it-somewhere!

Martyn

Quote from: martyn on March 20, 2025, 06:00:36 PMThanks for the quote from Ossie Nock's book 'LNER steam', John.

This was one of the first railway books which I bought, and I may even still have it-somewhere!

Martyn

Many thanks, Martyn.

Me too!

Do you remember the Pan paperback editions of some of the David & Charles railway books?

These came out about 1971 and I could, now and then, just about afford the 9/- or 10/- they cost. That was my first copy of LNER Steam.  And, yes, I have it still. It's sitting beside me as I write this.

I know there have been detractors over the years, but I rate OS Nock highly as a railway author. Nowadays, we are probably less interested in the performance logs which were popular in steam days, but there is much to be learnt from his works.

Likewise, the SuperStylish writing of Mr Nock's contemporary, C Hamilton Ellis.

I'm well though writing the next part of this amazingly brief mini-series. I have a notion it will end up as two parts!

Thanks again and all good wishes.

John