Steam speed records including City of Truro and Mallard

Prove it.

1) What percentage of BR's total operating cost in, say, 1950 was spent on coal?
2) What real-world percentage saving in coal did Chapelon's locos achieve (i.e. including all coal burnt on standby, lighting up etc - so not just when they were operating at peak efficiency).
3) From 1 and 2, what percentage of BR's total operating cost would have been saved even had they had about 20,000 locos all designed to Chapelon's principles?

If you can provide those numbers - fine, I'll be convinced. But until then, I'll stand by my view that fuel is only one of many costs in providing traction; and traction is only one of many costs in running a railway. Even a 10 or 20% saving on a minority cost only generates a minority saving.

Tom

 

Interesting thread drift from dubious UK speed claims to their railways did not care for power and coal economy of locomotives?

 

“Dubious”

Come on Hermod, I have defended your right to speech in this thread. Please don’t make it impossible to discuss this rationally with you.

 

Agreed - I love this kind of thread drift, that’s often where we learn the most about a subject by coming to it (or moving slightly away) on a tangent.

 

You are misinterpreting what I wrote.

Of course coal was a major cost. The four grouped companies had a collective working expenses that was I believe north of £100m per year - billions of pounds in today's terms. So even a minor expenditure would likely have had armies of clerks compiling stats, and managers out to shave off amounts here and there, whether in procurement or engineering as appropriate.

But there is a difference between saying that there was a management focus on a particular line item of cost, and saying that efficiency gains were anything other than "minor". Even on a really heroic set of assumptions:

- Coal cost 20% of a railway's total working expenses
- Chapelon could deliver 25% fuel savings per loco adapted
- Every loco in the fleet was adapted
- The cost of adaptation was zero (so no additional costs of equipment or additional maintenance on the debit side)

then you still only get a net reduction of the railway's working expenses of 5% - which I'd say is minor. And that is on a pretty heroic set of assumptions, notably that the efficiency gains were both deliverable in the real world, and applicable and implemented across the entire locomotive fleet. In practice the actual benefit was much smaller - hence my description of it as "minor". It's down to the advocates of Chapelon to demonstrate otherwise.

Tom

 

In France the cost of coal transportation had to be added, given the location of mines they had to send coal trains the length and the width of the country.
The conversion of the King 6023 needed only a newly produced fourfold orifice at a 2019 cost of 100UKP and made it a lot more economical.
Not doing anything is throwing money around!
Kind regards
Jos

 

Indeed, and that potentially tips the balance between prioritising thermodynamic efficiency and, say, prioritising maintenance costs (or any other cost).

But that rather illustrates the point that Chapelon didn't deliver a revolution: had he done so, everyone would have chased the thermodynamic gains to be had. Rather, he delivered a marginal improvement that tipped the balance in a particular set of cost circumstances, but not in others.

You only have to go to the other extreme of the US and look at the path chosen there: given the choice between burning more coal or employing more labour, burning more coal won hands down every time. Hence a loco that could pull a 5000 ton train with a crew of two, a mechanical stoker and clouds of black smoke was preferable to some finely honed machine that could deliver 50% more thermal efficiency but required 5 locos and 5 crews for what one Big Boy could achieve ...

The proponents of the cult of Chapelon seem to ignore the specific financial circumstances that made his locos work in some places and not others, and instead fetishise thermodynamic efficiency as if it were the be-all and end-all of locomotive design. No shareholder ever got a dividend because a railway's locomotives won prizes for efficiency. They got paid if the railway could generate more money than it cost to operate - a very different criterion.

Tom

 

You omit the other side of @JJG Koopmans' post, which is that some improvements are at such low cost that not doing them is throwing money away.

 

I thought Chapelon rather like Gresley was about delivering sufficient power to meet objectives laid down by his railway, for example 600 tonnes at 120 kph within the loading gauge etc constraints. Is that wrong?

 

Well, to a point - though if such gains were really there and really that cheap, why weren't they widely applied? Which makes me wonder as to how deliverable they were in practice - or at least if they delivered all that is claimed in actual service.

It's not as if the big railway companies didn't have experimental departments, and didn't engage in testing of locomotives in service. So clearly there was an appetite to improve locos - which makes me wonder why if Chapelon's improvements (or even lesser changes delivering more modest improvements) were so attainable, why no-one in Britain went down those lines? I don't believe it is just a case of "not invented here" - rather some combination of that improvements were more expensive than is being claimed (licence costs?); they delivered less in actual practice than is claimed; and that there were other avenues that absorbed the available scientific testing capacity more profitably.

Tom

 

I don't think you can call a 5% drop in expenses minor Tom. If you consider that AIUI the big four were marginally profitable at best then a net 5% drop in operating expenses without any loss in revenue would be a stupendous gain. I'm sure your back of an envelope calc overstates the case, but anytime you can reduce expense without impacting revenue then you're going to make a big jump in profitability.

 

Yes, but the assumptions to get there were pretty heroic - not least that you applied the developments to every single loco in your fleet and they all gave similar savings in coal cost. So firstly that is likely to take you about 30 - 40 years to achieve (see discussions passim about loco fleet replacement rates); secondly that the gain applies to everything. Is "Chapelonisation" going to give the same coal savings to a shunting loco as it gives to a mainline express loco?

Hence my characterisation of somewhat heroic set of assumptions. I suspect the real benefit that could be delivered in practice would be a fraction of that.

But ultimately - prove me wrong. In other words, show me the 1950s (or 1930s) business case that it would have been worth pursuing in this country.

Tom

 

Well, the Coal-Board changed a lot of locomotives along this line, they must have had some reason to believe in it!
Kind regards
Jos

 

I may be wrong, but I thought Gresley was influenced by Chapelon. Streamlined steam passages, Kylchap exhaust, double chimney. Were those not Chapelon inspired?

As regards the recent improvement to 6023's exhaust, was that not only recently necessitated because they sawed about 6 inches off the original chimney height to fit the new Network loading gauge. Would it have been of any benefit within the GWR loading gauge?

 

On seeing your superimposed diagrams, my first thought was that a Reichsbahn cab was a lot more spacious than a Churchward cab!

In British terms, the German pre-WW2 boiler designs seem close to Raven NER boilers. Combustion chambers were not used, but in the earlier South German 4-cylinder compound Pacifics, tube length was kept down by pushing back the front tube-plate (possibly to save weight?). In the Bavarian S3/6 design of 1908, the tube length was 5.25m (17ft 3in). But in the DRG standard Class 01 Pacific of 1925, the boiler barrel became much longer at 6.80m (22ft 4in) - the reverse of the way British design was moving at the same time.

After WW2, the West German Bundesbahn began to use combustion chamber boilers, in the new Class 23 2-6-2s and in reboilering of earlier locomotives. It was some of the most modern classes that most needed new boilers, due to a bad design choice in the 1930s. The Reichsbahn had began to use a new stronger type of alloy steel to allow higher boiler pressures without using thicker plates. It was discovered after a few years of use that the new steel was corrosion prone.

This web site has diagrams of some of the German classes, which you may wish to compare with GWR and other types:

http://dlok.dgeg.de/73.htm

Whether or not it was sophisticated, the Class 05 could clearly run fast and develop a lot of power, so I did wonder whether any Chapelon influences had been taken on board during its design. I guess that the reports from France may have prompted the designers to check the adequacy of steam passages and valves, but it looks from post #116 by @Hermod, quoting Prof Nordmann, that they didn't go as far as they might. In spite of having only 24 flue tubes, the Class 05 had a very large superheating surface at 90 sq m (968 sq ft) with a "Wagner three-loop" superheater, but it did not have a Kylchap, Lemaitre or other sophisticated exhaust system (Royalty payment concerns?).

It should perhaps be mentioned that Germany in the inter-war period made significant progress with main-line electrification, as well as developing high-speed diesel railcars. So steam loco development was not as central to the DRG as it would have been for the GWR/LMS/LNER. Nevertheless, the Reichsbahn developed the 01.10 and 03.10 3-cylinder streamlined Pacifics and ordered large numbers just before WW2 brought a halt. According to "The German Pacific Locomotive" by David Maidment, the Class 01.10 was initially plagued by teething problems and seen as a disappointment, offering little improvement over the 2-cylinder Class 01 of 1925. After the war, engineers removed the streamlining, sorted the teething troubles and provided some replacement boilers. But no more high-speed running. If a Class 05 with 2.3m (7ft 6in) wheels could do 200 km/hr (124 mph), then one might expect a Class 01.10 with 2.0m (6ft 7in) wheels to manage 174 km/hr (108 mph). But I have seen no indication that a Class 01.10 got anywhere near such a speed. They were, however, good enough to remain the premier express locos on DB steam-worked routes until steam was phased out, and to be revered by latter-day steam enthusiasts.

 

Streamlining the internal steam passages were already happening in varying degrees on LNER by the time Chapelon was well known.

At best, you could argue that Gresley and Bulleid adopted some manner of his best practice, but they still didn’t take it as far as Chapelon did with his locomotive designs. Which likely is down to trade offs in manufacturing and maintainability.

Even with, for example, the monobloc on the original P2 no.2001, the internal steam passages were improvements on the classes Gresley had previously produced.

It was not optimised, which is something Chapelon was very good at doing within the confines of design and testing.

The Kylchap arguably owes more to Kylala than Chapelon, as he came up with the original design and theory, and Chapelon made the existing patent more efficient.

Double blastpipe arrangements are not unique to Chapelon - he didn’t invent them.

Again, the onus is on the pro Chapelon crowd to prove he set the world alight - all the evidence is saying to me that he was an excellent theoretical engineer, was able to optimise old technology and adapt it to produce some stellar performance out of them, but his influence really wasn’t as wide ranging as is claimed.

Compare his influence to De Glehn - many locomotive designers around the world made use of his bogie arrangement. How about Bissel? Known the world over for his pony truck design. And so on… these are the comparisons you have to overcome to prove “influence” - the question will always be “to what extent” and “can we back this up with evidence”.

 

Agreed but he refined the arrangement with the splitters and cones. Nobody would claim that the plain double blast pipes as applied by the LMS and BR owed much if anything to Chapelon but the exhaust arrangements fitted to LNER designs most certainly did.

 

Chapelon's first rebuild, that of Pacific 3566, produced an increase in power of 62% and an improvement in economy of 25%. Reference is Col Rogers' book. Minor? What English railway director of the 1930s would have called that minor? Unfortunately, something like that was never offered to them.

 

Although @Hermod did use the term "revolution", few of us have claimed that Chapelon's influence was wide ranging. That was prevented by a combination of time for ideas to catch on, WWII, replacement of steam by diesel and electric and (at least in the UK) some application of the KISS principle to the BR Standard locos. A few disciples applied Chapelon principles in a few countries, but it was too late for widespread adoption.
The claim is rather that Chapelon produced major improvements in both thermal efficiency (which is useful but as has been said on this thread not of major importance to most railways) and power-to-weight ratios, which surely were of benefit in allowing increased loads without needing bigger locos.

Edit: BTW, shouldn't a lot of recent posts here be moved to the Chapelon thread?

 

Setting aside issues over the source, those figures have very limited value without the absolutes. If we're to draw conclusions from them, we need to understand what those percentages are in comparison to, and therefore what the equivalent would have been in British practice.

This is before we consider cost vs. gain, or whether the same degree of change would have been possible within British loading gauge restrictions.

Recollecting the history of very high power locomotives, notably the P1s, it would also be interesting to understand whether British railways would have had the capability to absorb such extra power.