Steam speed records including City of Truro and Mallard

Here's a clue:

What was it that Bulleid is quoted as saying? "Thermodynamics never sold a single locomotive". Did he have a clue as to what Chapelon was doing (and achieving)?

 

You are absolutely missing the point. Evidence that a revolution took place has to show that there was a major, and sudden, change in practice. "Here's a problem ... here's a solution ... here is widespread adoption of the solution" What you have pointed to is simply diagnosis of a problem. Chapelon is supposedly the answer to that problem - but unless you can point to widespread adoption of his ideas, there is no revolution.

Bulleid was right in as much as thermodynamics is only a minor part of the whole life operating cost of a steam locomotive. Availability is more important (arguably Bulleid's locos had problems there, but it is unarguable that high availability was one of his design goals - so he had correctly diagnosed the problem even if he failed to solve it adequately).

In cost terms, shuffling individual wagon loads of freight around at low speed between signal boxes that required two or three shifts per day every couple of miles of track was a crippling cost. Introduction of modern centralised signalling control was a genuine revolution in railway operating costs, as was elimination of unbaked wagons. Tweaking the theoretical (not real world ...) thermal efficiency of a locomotive from 7% to 10% and applying that to just a few percent of the total operating fleet was scarcely noticeable in cost terms.

Tom

 

I'm inclined to think of the last generation prop fighters like the Supermarine Spiteful. They were a significant advance on what went before, but that was largely irrelevant because the jet engine had rendered them pointless (outside the temporary niche of carrier operation until angled deck carriers were available).

 

Mr Diamonds paper from 1947 page 411-412 .

Mr Cox (who designed steam locomotives for a living) describing french steam before and after Chapelon and world influence

SBN 711000794

05 was designed and built before the Chapelon earthquake.

Some three cylinder locomotives were born with conjugation and rebuilt

The other way much less I think. Seven Raven B16 spring to mind

 

Or an even better analogy, the turbo-compound aero engine. Absolute black magic in thermodynamic terms relative to contemporary (late 1940s) piston engines, but a dead end given the rise of turbojets.

This gives a good overview about the problem they were there to solve, and how they work, and ultimately why they are now just an interesting engineering dead end. The point about the high maintenance costs is germane: essentially you have a piston engine design that is efficient enough to give the desired range (cross Atlantic or cross-Pacific) for airliners on a reasonable fuel load, but at the expense of really high hourly maintenance requirement.



Tom

 

May I recommend reading mr Diamonds paper page 411-412 and the rest as well?
(Searching for link)
Bulleid was world class:Totally unreliable locomotives with loussy thermodynamic and very expensive.
He even knew Chapelon personally.

 

So much this!

 

So Chapelon published his paper in early 1935, which showed a path towards significant motive power efficiency gains in the steam locomotive. This was, at that time, largely theoretical and with limited real world experience.

At the same time, Gresley was well advanced with what became the A4, where the first production locomotive was delivered in September 1935.

Before the historian in me gets excited about the "missed opportunity" this represents, he'd like to understand what it would have taken to compress Chapelon's ideas to UK loading gauge and then prove them for production use on the LNER.

 

If locomotives have fourcylinders and can earn money without ever going more than say 80mph five feet six drivers are more than enough

ChapP2 by Hermod posted Feb 6, 2018 at 10:13 AM

SNCF 1-4-1P 5 kg steam per IHPH Worlds best below 21 bar BP.Outside HP cylinders 16 inch

The real missed opportunity was mr Diamond that told Fowler before Chapelon that LMS Compounds had Lousy valves and mr Cox stating later that a Fowler proposed 4-6-0 three cylinder compound could have been a world beater

 

Where Cox is concerned, I’m afraid I’ll take my views from the BR Standards - far from the most advanced locomotive designs of their era, and where Cox was a significant part of the design team.

More generally, when someone involved says an idea could have been brilliant, but didn’t then progress it or similar, it raises questions about how great they really were.


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That to me is at the heart of the problem. All very well and good claiming Chapelons ideas were excellent - and they may well have been - but I think when you look at it in the round, his actual influence for a variety of reasons is minor.

The one thing which strikes me is the timing. Post war Chapelons approach was Canute like. Electrification was coming across the world and that was what should have been the emphasis.

As much as we love steam locomotives, even things like the speed records we’ve debate of late have to be contextualised for the time they took place in. Mallards steam speed record was eclipsed by diesel and electric records at around the same time.

I remain unconvinced in the main by Chapelons proponents - and the more reading I do, the more I note elements of confirmation bias, particularly in Colonel Rogers book on Chapelon.

That is not to say that Chapelon wasn’t intelligent, didn’t produce some extraordinary locomotives, probably was a genius - but his actual influence and relative importance in the history of the railway and the steam locomotive remains small and with likely good reason.

And it has nothing to do with “not invented here” syndrome, IMO - evidence of influence is lacking.

 

And a further point - though I am aware it is at odds with the thread title - but in running a railway, the ultimate performance of any steam locomotive design is entirely secondary to the efficient running of the railway. Tom is, I suggest, on the money that availability and cost to run is more important than a few % on thermal efficiency.

 

May I say, with some exasperation as I am researching Bulleid at the moment as a side project, but the vast majority of his locomotive designs were not “totally unreliable”.

The more I have looked at the primary evidence of his original Pacific’s the more convinced I am that this was a convenient myth to allow for a rebuilding.

When I am able to I’ll start a Bulleid thread and we can put to bed some of the nonsense.

Besides which the Bulleid boilers were excellent steam raisers, and always have been…!

 

I'd venture to suggest that the BR standards were the best all round locos produced in this Country. I've yet to meet a footplateman who doesn't like them unless they are biased in the first place.

 

Chapelon was surely unlucky in developing his ideas, designs and follow-up proposals in France, at a time when the turmoils of that country before, during and after WW2 prevented their proper adoption and development.

 

Quite possibly. But they were also a very conservative set of designs, that did not progress steam locomotive engineering materially.

When someone is cited in support of a proposition for technological advancement, but was part of such a conservative design team, I'm afraid I'm very sceptical about the credibility of the story.

For clarity, I've no opinion for or against Cox beyond that point.

 

Correct, but it is a revolution that should have occurred, in England at least. A 50psig loss in pressure between the boiler and cylinders? A bit like attempting a speed record with the regulator partially closed!

Minor? Really? I suggest that you do some more research on the results achieved by Chapelon.

 

He likely was, but that doesn’t mean we should elevate him to a status that doesn’t match the evidence.

I have argued consistently that there are more important names in railway history - where the steam locomotive is concerned he is much loved with good reason, but an evidence based approach is key to all of this.

One could cogently argue that the standards were not meant to advance steam at all: more to make steam last until other technologies were funded or advanced enough to depose them.

And you could further argue that they filled that role perfectly, but were also somewhat wasted for working lives.

I do not see that developing a range of simple to build and operate steam locomotives for a changing world wasn’t advancing steam though - it was advancing it in very different ways. Thermal efficiency be damned, how does this loco get fixed or prepared on shed? How do we make life easier and cheaper for us in a world where getting staff becomes more difficult for the dirtiest jobs?

This is why the focus on IHP/DBHP/HP all seems to me to be completely missing the point of running a railway. It’s so much more than the extremes of performance.

 

One could, and in another context, I might. But in response to the argument advanced by @Hermod, my view remains that the witness's credibility is undermined by his own subsequent work. I make no comment on the Standards, save to observe that they would make an interesting subject for review against the various themes explored in this thread.

 

My understanding is that the point of the BR Standards was not to advance the thermodynamics or performance above that of the engines of the Big Four, but to equal those performances with reduced preparation, disposal and maintenance times.

Sorry to disagree, Steve, but I was on the Railway in 1973, not so long after the end of steam and it was still an occasional topic of conversation. Generally, the men I worked with at Edge Hill weren't over-keen on the Standards. They didn't exactly dislike them but, for instance, preferred a Black Five to a Standard Five. My feeling was that they didn't see the point: they were no improvement above what they replaced except, as mentioned above, in preparation and disposal. On the road, they were no better, and that's where they spent most of their shifts.