Chapelon and related Matters

On what evidence is that statement based? Try expressing that opinion on a French forum! On the contrary, there was hardly a locomotive built in France after about 1930 (and probably earlier) that wasn't influenced by Chapelon.

 

Simon, when you state “Chapelon’s actual influence in France is small” I wonder if there is
any point in this dialogue continuing.

However, one final thought. Whether 10 or a 1000 locos were built or rebuilt to a Chapelon
design whilst interesting is not an indication of design ability.

I have been thinking, if I were to be asked to sum up Chapelon’s inheritance briefly what
would I say. I have always been fond of analogies.

Perhaps as an analogy: Gropius ( and the Bauhaus ) personally designed only a few
buildings ( compared with some lesser known architects, particularly in Europe). It is
his influence,( both in founding the Bauhaus and his various writings and lectures ), that
places him at the very forefront of twentieth century architecture. Chapelon has
IMHO a similar position with respect to steam locomotive design. Where the analogy
breaks down is Gropius was in at the start of a movement, Chapelon was facing the
challenge of a falling market ( steam losing out to other forms of motive power.)

In modern parlance ( if I understand correctly ) Chapelon was inter alia, a
supreme ‘influencer’.

Michael Rowe

 

Goodness, I ventured an opinion Michael. That’s quite an extreme response.

That I can agree with, but design ability isn’t the same thing as influence.

But you still haven’t provided evidence of influence, direct or indirect. Did Chapelon’s work on steam wake up a few people designing electric locos for French railways? You could say yes, there’s anecdotal and primary evidence to support that.

You say there’s international influence that Chapelon had, I ask what that is, the answers remain vague. It’s on you to prove his influence, not me. You’re the one making the statement.

On the evidence I’ve been provided I remain to be convinced. I’m open to having my mind changed, but “influential” tends to have, as Tom said yesterday, some effects which are tangible and provable.

See above.

Again, where is the evidence for that view? We can see a lot of work done on a few prototypes and some changes to a few existing classes. If he did influence them, in what way was he influential?

 

One comment I might make is to what extent did Chapelon move steam locomotive engineering along, not so much in the sense of everyone adopting his ideas which is easy to see but in terms of making it clear that there were improvements to be made and this encouraged others to innovate even if they did not follow what he did.

 

Viewed through that lens, his collaboration with Gresley and Bulleid at Vitry can be seen as influence.

 

I'm enjoying reading this thread. Would you consider Porta and Wardale to be more "practical" engineers (whatever that means) than Chapelon?

 

Nowhere was your name mentioned. Xenophobia isn't exactly racism but it is on the way.

 

I think there’s no doubting of the excellence of some of Chapelon’s locomotives, 242A1 in particular (though I prefer Marc De Caso’s 232U1 personally, from an aesthetic standpoint) and there’s no doubt that his engineering had merit if the focus was on improving steam continuously.

I would argue though to have the title of the foremost locomotive engineer, you have to be influential and you have to have made a positive contribution to the railway you’re working for. Porta and Wardale maybe suffer from this too to some extent, by the time they were developing their designs, steam was on the way out and diesel/electrics and electrification were in the ascendency.

We can appreciate Chapelon’s design flair, his scientific understanding and the locomotives he produced, but ultimately we need more meat on the bones for influence, for sure. Not just my opinion, according to this thread.

 

I didn't think we were discussing such a claim.

 

What I do like about Wardale is that he understood that the loco was part of a system and how improving loco's could then feed through into the operation of the wider railway.

One obvious point that he did make was that when a section of SAR was dieselised the huge number of fuelling/servicing points that were closed as a result.

The other point of course as far as the UK was concerned IMHO was that we didn't need to modernise our loco fleet we needed to modernise the whole system, in particular the wretched unfitted wagons that infested the network until the early 1990's

 

Absolutely correct.

See where above?

A few prototypes? For example the new 141Ps consisted of 318 examples. They were the equal of the 242A1 with regard to grate area. You are just showing your lack of knowledge of French steam.

 

In my post with that quotation I have those details. I suspect you are, as you have been before with me, being deliberately obtuse and provocative again.

By definition, these are not prototypes. They are a production run.

My understanding is that he was not involved in the production process as the main advisor. See below:

https://www.241p9.fr/history-1-the-241-p-serial/

Which to me indicates a hierarchy similar to Gresley and Spencer. We don’t give Spencer credit for the Pacifics, we give them to Gresley whilst acknowledging that Spencer was an excellent engineer and designer in his own right.

If I may be so bold - I’ve provided citations for my understanding, which appears to be largely correct in its interpretation.

The above would seem to indicate that I’m not, but you may be.

 

With respect, it has been said in this thread and I have challenged that. I am not alone in challenging that.

 

Not at all. I'm still none the wiser.

Actually it was you that implied that Chapelon was only involved with a few prototypes etc. Nothing could be further from the truth. My statement was intended to indicate otherwise.

Yes, correct. He was excluded from the 241P by ex-PLM SNCF officials until Schneider of Le Creusot (the builder) contacted him because the exercise was not going well. However, it was too late to correct the thickness of the frames - a feature common to PLM locomotives. They never equalled the performance of Chapelon's 240P, which were soon to be rendered surplus to requirements by electrification, even though the ex-Nord region was begging to use them.

 

You appear to be mixing up the 241P and the 141P in the same argument. There was quite a reasonably significant difference in when these designs happened and the 241P was somewhat contentious; probably not the design Chapelon would have wished for.

 

I did indeed misread the original post. Thank you for alerting me to that. I will go away and do some further reading and come back.

 

This is a reasonable question, although the 05 class is not exactly the shining example of wide scale deployment I'd have chosen.

First off, I should make it clear that I view testing as hugely important. No design is finally proven until tested. You can test and iterate your way to an excellent design. But without a good theoretical underpinning, changes will tend to the incremental and can also be counterproductive (see Trick valves for an extreme example; let us maximise the flow of steam into the cylinder and not worry about how to get it out).

Whereas if you have a reasonable library of real world technical data (and Chapelon appears to have had this for a lot of previous French designs, down to steam pipe cross section and details of valve ports), and are armed with a robust and testable (from the data) theoretical model of what is going on, you can make much larger extrapolations without fear of moving too far out of the known realms.

That, I argue is where Chapelon differed from his UK contemporaries. The better UK designs had, in my broad brush opinion, reached a point of incrementing forwards from the Churchward model in thermodynamic terms; everyone had just about caught up with respect to valve events and boiler pressures and the other lines were pushing superheat up. The W1 certainly represents an interesting diversion from this, by the way, but by and large the improvements remained incremental.

By comparison, with Chapelon’s first prototype he was able to analyse the existing technical data and specify large changes with confidence. And it worked, the combined effect of a simultaneous barrage of modifications being a complete transformation of the performance of the prototype in 1929 and subsequently the class. The data he presents on the incremental effect of the various improvements applied to different versions of the design was actually generated later, when presumably lines were trying to work out what they could leave out from the complete package of rebuild work. These and 3566 considerably expanded the known world of steam locomotive thermodynamics for the more empirical designer and not coincidentally steam circuits promptly started to receive more attention; the 1930s designs show a considerable step forward from the 1920s examples.

Without the analytical underpinning, it is much more difficult to confidently justify big changes outside the realms of existing data. Gresley himself, in the address I was originally quoted, made the comment that:

“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.”

No real novelty. Anyone could have done it. But the P2 steam circuit came well after 3566, five years later, the A4s later still. Chapelon actually did it, and proved them in service for everyone else to see.

 

One might note that it can be argued that there wasn't much real novelty in Churchward's types, and they were much more a synthesis of ideas from different places brought together in a harmonious whole that was more than the sum of its parts.
I think if I were looking for evidence of direct Chapelon influence I would start with the proceedings of the iMechE and in particular discussions after papers. One thing worth noting though is that I don't believe there's much written by UK late steam engineers that doesn't have some passing mention of Chapelon. I'm not sure that's true of many other foreign engineers.

 

Sorry, this is a website that quotes from a book. Imho this is "scientific" hearsay!
Chapelon himself discussed these locomotives in his 1952 book, p.345 and refers to their description in Chan & Thomachot, Revue generale des Chemins de Fer Febr. 1949.
His role in the design should be studied from the earlier mentioned Escudie book. Regarding him as an adviser subordinate to the CME is not really the way Frenchmen think!
Kind regards
Jos