Chapelon and related Matters

That is still not evidence Michael. That is secondary evidence at best. It gives no examples of influence that we can analyse. Just because Cox says it, does not mean it is true.

Let's talk this through. Cox states it has been picked up in other countries. Okay, let's take that at face value. Can we prove this happened and also show this influence, for compounds or otherwise? Has anyone in other countries gone on record to list Chapelon as one of those influences? That for me would be a better piece of evidence than Cox's vague statement.

In terms of simple expansion engines, I would argue strongly that streamlining of internal passages and opening up of the steam circuit was happening outside of Chapelon by a range of locomotive engineers, borne out I think by developments shown here and abroad. Gresley was doing it prior to Chapelon, and the results of his work in this area are clear for all to see.

Bulleid with his work on the LNER P2 design actually led in that field (whatever might have been alleged about the wheelbase, the steam circuit and boiler was excellent) his work culminating in his Bulleid Pacifics for the Southern Railway.

I think (and I say as much in my book on Gresley) that Chapelon's influence on Gresley was more minimal in comparison to Gresley's influences on Chapelon, particularly where the prototype W1 is concerned. William Brown also noted this in his book on the W1 - Chapelon, thanks to the more generous loading gauge and free from the pressures of running a railway, was able to set up his compounds as Gresley originally intended for the W1 and produced excellent results.

 

In 1925 Bulleid was sent to Tours to observe the trials with rebuilt Pacific No. 3566. Gresley himself, later in 1925, visited Chapelon. As a result of this visit, Gresley decided to fit a Kylchap exhaust to one of his Shire Class 4-4-0; Chapelon supplied the drawings and a single Kylchap was made and fitted by the LNER. However Chapelon after riding on the locomotive, discovered that a mistake had been made in the construction of the assembly. The four lobes of the Kyala spreader, instead of being entirely separate from one another, had been connected just below the top by iron ties, thus creating an obstruction which impeded the gas flow through the centre of the apparatus and prevented it from functioning properly.

Gresley’s No. 10000 did not come up to expectations. Both Gresley and Bulleid had discussions with Chapelon on what could be done to improve it, Chapelon pointed out that the degree of superheat was insufficient to avoid condensation in the LP cylinders and that it should be increased; he added that even better results could be achieved by re-superheating (as used on 160.A.1) and that the fitting of a Kylchap exhaust would help.

The double Kylchap exhaust, rotary poppet valves, wide steam passages and high superheat of the P2 were all copied from the rebuilt PO Pacifics. Gresley, in his second Presidential address to the Institution of Locomotive Engineers in 1936, said, “I did not hesitate to incorporate some of the outstanding features of the Paris-Orleans Railway’s engines, such as the provision of extra large steam passages and a double blastpipe. There was no real novelty in these features but the French engineers had worked out the design scientifically and had proved them by the results obtained in actual service.”

One problem with No. 2001 was that, contrary to other locomotives of the same class which were fitted with piston valves, it was necessary to increase the diameter of the exhaust by 50% to avoid having too great a draught. This problem could be attributed to the excessive temperature of the exhaust steam through poor design of the cylinder block, resulting in the exhaust being heated by the incoming live steam. This feature has been studiously avoided on No. 2007.

Although Gresley had incorporated many of Chapelon’s ideas in the design of the P2, it was clear that he had failed to build a locomotive equal in either performance or efficiency to the French rebuilds. Gresley told the Institution of Locomotive Engineers that the first P2 would be the last of its type and any subsequent P2 class would incorporate the lessons learned in France.

 

I thought the design of the P2s was discussed with Chapelon. Certainly Bulleid travelled
with the P2 to France and was involved with the Tests both in the Testing Station and
out on the road as was Chapelon.

Simon, yes it’s secondary evidence and Cox has often attracted criticism. The Stanier quote
which I added to that post hopefully carries more weight.

I was intrigued by your list of engineers. If you mean in the 1923-48 period then I find
two each GWR and LNER engineers surprising. If you mean LNER and GWR pre
1923 as well then I can settle for Gooch and Churchward., Ivatt and Gresley.

I do hope, although reference to exhausts make me wonder, that the Austrian is
Gölsdorf.

I assume the French candidate is De Glen. Not sure having imported his three
Atlantics that Churchward actually took too much notice. Jim is far better
qualified to comment.

I assume the Argentinian is L.D.Porta who I have always understood in his own
words took Chapelon as his starting point.

If I may add one thought. Whilst in the UK the CME was king in many parts of
the World designers/engineers were afforded less prestigious positions.

Michael Rowe

ps I had not read RAB3L’s post when I wrote the above.

 

The film 'The Train' is on the iPlayer at present, for those who haven't seen it

 

Here's a thought. We know that in the 1950s Sam Ell's design and testing regime at Swindon made major advances in the steaming of various types, mainly by refinement of front end design. Now what were his influences? The date is certainly right for his having been influenced by Chapelon, and we know from above that there were people at Swindon who read Chapelon. I really know far too little about Ell, but it might be an interesting area for study. There are various papers he wrote for Institute of Locomotive Engineers and others which I don't have access to, but might be worthy of study.

 

1). The de Glehn bogie fitted to all GWR 4-6-0s of the 20th century.
2). The divided drive of all 4-cylinder GWR 4-6-0s where the inside cylinders drove the leading set of drivers, the outside cylinders driving the centre drivers.
3). If you look at photos of La France, you will see where the Star/Castle/King slidebars originated.

I'm sure that this list is not exhaustive!

 

And this to me is the key quote, from the man himself no less.

Chapelon quotes a lot of designs in inspiration for his work, unsurprisingly with a heavy French bias (although including Cramptons). But he worked out the requirements for how much he needed to improve features scientifically rather than empirically. The A3 was a step in the right direction but the improvements were not carried out through the whole steam circuit, even when the cost would have been a larger pipe, because the scientific rigour in carrying those improvements through the complete steam circuit wasn't fully there. 3566 went most of the way in a single prototype which paved the way for similar rebuilds.

Like a lot of good ideas, what Chapelon did seems obvious in retrospect, almost trivial. But nobody did it so thoroughly or scientifically before him, and several designs after him (yes, even in the UK) show a realisation of how far these improvements could be carried where before they might have gone up one size in the pipe, found an improvement and called it good.

 

Chapelon's No. 3566 started trials in 1925. Gresley's No. 10000 wasn't completed until the end of 1929. So where did the idea that the W1 would be a compound originate?

How many of Chapelon's innovations were included in Gresley's locomotives compared with vice versa?

 

Yes of course there is usually a trade off between cost and benefit, but that looks to have been very positive with Chapelon's rebuilds. Acceptance or rejection of proposed improvements is also very often influenced by a "Not invented here" attitude.

 

Absolutely. But that doesn’t mean that all innovations are transferable in practice, because of the underlying conditions.


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Source required for this - my understanding (drawing on RCTS and RAIL 394 locomotive committee minutes) is that two D49s were fitted with a Kylala blastpipe. Chapelon did advise on this fitting, but it wasn't Chapelon's Kylchap that was fitted.

Double Kylchap was subsequently fitted, locomotive performed to the equal of an A3 and with decent coal and water consumption.

A reminder to those here that it was Bulleid who was largely responsible for the design of the P2, Gresley making recommendations where necessary. He was focusing on the W1 development and the forthcoming A4 primarily.

"Many of Chapelon's ideas"

What are these ideas? Can someone on the Chapelon side of the debate please give us some actual pointers for what was actually used? I can see how no.2007 has avoided some issues of no.2001 but it is not clear where the Chapelon influence is.

Gresley worked for the LNWR and L&YR, both of which used compounds in some capacity (which he observed and worked on as an improver at both railways).

When working under Ivatt at the GNR, he helped directly with the preparation of several compound Atlantic locomotives, one of which was fitted in a similar fashion in terms of valve gear to how the W1 would later be set up.

Gresley therefore had ample experience with compound locomotives far in advance of meeting or discussing with Chapelon.

That only matters if Chapelon actually produced anything in reasonable numbers to attest to the excellence or otherwise of his designs.

Gresley used the Kylchap in a small way and the rest of his locomotive design is undoubtedly due in no small part to his time serving under Ivatt at the GNR, but modernised for the requirements of the day, and mostly based on his own experiences.

(And, if we're talking about pushing for a scientific process, Gresley was the leader, by far and away, of all of the locomotive CMEs of the 20th Century in comparative testing and employing scientific methods to improve his craft. His pushing for a national testing centre for decades, together with the work done with the National Physics Laboratory, is evidence enough of that, but there is more besides).

 

I remain sceptical that this is true, at all. Even if you just go UK-centric, there was a range of different CMEs experimenting in very similar ways in the same areas (not just Gresley) and the LNER, LMS and SR were all utilising both their own R&D resources and that of outside contractors such as the National Physics Laboratory for scientific research, particularly in streamlining casing and in the design of draughting.

If you go abroad, there were undoubtedly other engineers on railways conducting similar experiments to Chapelon, he was not alone in wanting to maximise the efficiency of the steam locomotive. I would say that Chapelon took his quest for efficiency to one extreme, other engineers were more pragmatic by comparison. (Best examples - look at the development of steam locomotives in Germany in the 1930s. There is no doubting the excellence of the 05 class, for example, and you would hardly say that the Germans did not do scientific testing there).

 

From here: https://www.lner.info/locos/D/d49.php

"During 1928 trials were performed with 'Kylala' blastpipes fitted to D49/1 No. 251 and D49/3 No. 322. Initial results with No. 251 were good, and No. 322 was fitted with a 'Kylala' blastpipe that incorporated some recommendations from Chapelon. The trial was cancelled in 1930 due to a lack of apparent improvement over a conventional blastpipe."

Why? Numbers may be due to the fact that Chapelon usually optimised his locomotives in one step. PO supplied Chapelon's 4-8-0s to PLM (even) and Nord -some were new, not rebuilds. Few locomotives built in France after 1930, weren't influenced by Chapelon's principles, so the numbers are questionable anyway. You also completely failed to answer the question. If you request references from others, maybe you should do the same?

 

Curiously, I am just listening to a podcast on naval history, and it talked about French naval officer cadres of the late 16th century.

Unlike the royal navy, french officers had a much deeper technical training on how the ships worked (the Royal Navy had the rank of ship's master who made the ship go).

Interesting how the approach repeats itself. (Also, it's interesting how on a macro scale, both worked)

 

So you were incorrect in the first instance, and my recollection was correct.

Because it is unarguably true that Gresley's work had more effect on the railway landscape than Chapelon. Gresley used steam as his primary solution to the LNER's transport issues but his principles were on a whole-railway approach (his fully streamlined and articulated high speed trains set the tone for today's high speed railways).

Is this true and can you evidence that?

I believe I have now answered the question more directly above.

I did, I have quoted Rail 394 and the RCTS volumes, as above. What would you like a reference for?

 

The beauty of railway engineering is that it's not a one size fits all solution to everything.

In terms of the historical value, everything needs to be examined on its own merit and assessed against a good framework for understanding the topic.

 

Not at all. From above: "and No. 322 was fitted with a 'Kylala' blastpipe that incorporated some recommendations from Chapelon". Chapelon supplied drawings but they weren't implemented correctly. Chapelon even rode on the locomotive in question and pointed out the error of construction.

Nobody rebuilt any of Chapelon's locomotives, not even Chapelon himself. You can't claim that for Gresley. Did Gresley build anything to match the power and efficiency of Chapelon's locomotives?

 

Surely there you are confusing quality and quantity. If even a single locomotive from designer A establishes that certain design features are effective and worthwhile, and designer B then incorporates those in one of his* locos, that demonstrates the influence from A to B. If designer B continues to incorporate the same features in many of his locos that demonstrates that the influence was lasting.

*Nothing sexist here, because in the period that we're discussing few if any females were involved.

 

As an example, Chapelon/PO rebuilt 37 Class 4500 231s as 240A and 240P for the SNCF south-west and SNCF south-east respectively. Wikipedia doesn't list any difference between the two but there may have been minor differences. Is 37 not sufficient? There's also the 318 141Ps (358 were originally planned), built by SNCF from 1941. These were designed on the same principles as his Pacifics and 240s. They lasted almost until the end of steam in France - the 141Rs outlasted them by a few years because a lot of them were oil-fired. As a consequence most preserved 141Rs are oil-fired. There's only one charbon 141R preserved in France. 318 not enough?




Incidentally these locomotives were retired prematurely by SNCF (at this time most senior positions were occupied by ex-PLM personnel), even though the ex-Nord (amongst others) was begging to use them. Instead they were replaced with the 241P Class which was a development of the PLM 241C. Chapelon was initially excluded from the design but was eventually contacted by Schneider of Le Creusot who were building the 241Ps. It was too late to re-design the frames which were only 1.1" thick. As a consequence, the 241Ps suffered from overheating of driving axle boxes. In spite of their 54.3 sq ft grate area their performance never equalled that of the 240P class with only 40 sq ft.

 

No, you’re misrepresenting my point.

Gresley incorporated the use of Chapelon inspired double Kylchaps (these are ALSO attributable to Kylala - please remember that) and that is the limit of Chapelon’s influence.

Chapelon’s actual influence in France is small, therefore whether Gresley influenced him or not is less relevant than the opposite way - there’s over 1000 Gresley locomotives that were designed, and his valve gear was used in modest numbers in different countries too.

The onus is on Chapelon supporters to prove Chapelon’s influence.

Is this really necessary to explain?