Locomotive Performance and Tractive Effort Discussion

RCTS makes the claim about nickel steel boilers, and notes that some were used on 5101s at 200psi. However the boiler details in RCTS don't make a distinction. Its an irritation that RCTS uses their own classification for boilers and almost completely ignores the GWR boiler codes. Looking through my collection of weight diagrams 61xx and 81xx are marked as boiler class BB , and 51xx and 5101s as class BA, so there was a difference. Unfortunately I don't think I have any reference that says what the difference was.

 

That makes sense. The boiler on 4150 was marked as BB, subsequently changed to BE, whatever that means. Nickel steel?

 

On drawing 60593 No 2 BOILER 200 lbs psi, there is a small note-FOR Std BOILER No 2 WITH WORKING PRESSURE AT 225 lbs PSI SEE ATTACHMENT.
Unfortunately, I do not have a copy of the attachment. Didcot will probably have a copy in their drawings archive.

 

The A1, P2 and 71000 have been, or are being, fitted with double Kylchaps in preservation, although I suspect they are all the so called one size fits all LNER design.

 

Gresley had shown an interest in the Kylala-Chapelon double chimney and exhaust arrangement and in the July of 1933 Associated Locomotive Equipment was obtaining drawings for its application to the P2 class. It was found during trials with 2001 that the optimum blastpipe nozzle area was not always the one predicted by calculations. Testing on the LNER revealed that the engine steamed well with a total nozzle area of 50 sq. in. Chapelon considered that this figure was too large and that a figure reduced to around 40 sq. in. ought to give perfect evaporation. The testing at Vitry confirmed that the LNER findings were correct and it is possible that the heating of the exhaust steam due to the steam passages of inlet and exhaust being too close together may have contributed to this - essentially the exhaust steam got superheated by up to 100 degrees fahrenheit.

10000 was fitted in March 1935 with an exhaust designed by Ste. le Chauffage Integral, Paris. The designers noted that it had not been possible to apply the Kylchap design principles as accurately as would have been the case for a more conventional boiler and that the optimum would have to be found by experimenting with alternative sizes of blastpipe top and taper blocks.
Each blastpipe was bisected by what is termed a feather which split the exhaust stream and this split took place before the tip orifice which on this engine was 4 11/32" in diameter which could be fitted with one of four sizes of taper block which reduced the tip area in stages down from 17.5 sq. in. to either 12.0 sq. in, 10.9 sq. in, 9.5 sq in, or 8.5 sq. in. It should be noted that the smallest orifice tested on 2001 was 16.4 sq. in.

2751 had been the subject of smoke lifting experiments in 1932-33 and this engine was fitted with a Kylchap double blastpipe arrangement in July 1937 and this design was based on that fitted to 10000. The Kylchap cowls were identical as was the placing of the choke in the chimney liner though its diameter was increased to match that on the standard single chimney at 1 ft. 3 in.. The bottom opening of the liner was increased to 1 ft. 4 13/16 in and the chimney orifice 1 ft. 5 3/8 in. The blastpipe tip or nozzle area was 5 1/4 in. and when fitted with number 3 taper blocks gave a total nozzle area of 33.92 sq. in.

When 10000 was rebuilt it was fitted with an identical arrangement to that fitted to 2751 and not the larger P2 arrangement.

The arrangement fitted to the A4s were almost identical to that fitted to the A3 except that the tip was reduced to 5 in. and with the number 3 taper blocks, also known as Goodfellow tips, gave total nozzle area of 29.9 sq. in.

The rebuilt P2s, class A2/2 also had the A3 arrangement fitted and the A2/3 were similar except for the blastpipe orifices which were cast as a clover leaf shape in order to dispense with the taper blocks. The A2/1 fitting was identical to that fitted to the A2/2s.

The Peppercorn A2 was fitted with the A2/3 arrangement and the A1 was similar.

That arrangement belatedly fitted to 71000 was based on the A1.

 

The A1 was fitted with a Kylchap because that was what was on the drawings, and with no reputation for poor steaming or inefficiency why would you want to change that.
the P2 'Class also had various permutations of Kylchap exhaust, but as the boiler is to all intent an A1 boiler then using the same arrangement as Tornado is a good starting point
Surely the arrangement fitted to 71000 was based on the A2, Specifically 60532 and this was done as the existing arrangement was clearly wrong, and because notes on the original design recommended a Kylchap.... Those involved nay not have been receptive, or even aware of the work of Porta et al.

 

20% is a pretty wide window. Has the underlying theory received much attention since the new build was first mooted?

 

If you are going to fit an exhaust system fit the best that you can. The Lemprex is felt to be an improvement on the Lempor but the latter benefits from having more readily available design information supporting it.

 

Which pretty much confirms what I was saying earlier - there's no one standard fitting!

 

If we look at the roots of the design of Kylchap exhaust systems we have two companies one being Associated Locomotive Equipment and the other being Ste. le Chauffage Integral.

Railway companies did not design and manufacture everything in house. We are all aware of Gresham and Craven and Davies and Metcalfe. The names Silvertown and Wakefield are also familiar ditto Westinghouse.

The design of the Kylchap system was the subject of patents and licences, the intellectual property was guarded and protected, the same applied to the Giesl ejector.

If you wish to experiment with exhaust system design the information that you need is freely available now when it comes to the Lempor system, Porta wanted to share what he had developed. There are also those who have written books on the subject. The railway companies were not very scientific when it came to exhaust design and if you wanted an improvement it was very much empirical or trial and error. If someone had produced a system which could be designed and adjusted for purpose you had to pay for it. Others did the design work for you.

The Kylchap system used by the LNER works well enough. It can be optimised with trials in order to ascertain the most suitable blastpipe tip or orifice area and I would not describe the results of such trials as permutations but rather fine tuning. The system functions well on Tornado and should be satisfactory for the P2 even if a little adjustment be needed. If someone wants a better system then this can be produced but the Kylchap was a part of the original design and if it isn't broken it can be retained.

 

So little of the new P2 is consistent with the historical design- might as well alter the exhaust to optimise it I would have thought.

 

Given the number of alterations to the class (just as Mikados), there's an exceptionally strong case for saying their design detail was fairly fluid ... and for precisely the same reason the 7th loco, No. 2007 has received attention where historic experience indicated it was needed.

I fail to see an issue.

 

Me neither, think this was a comment rather than suggesting there was an issue.
Hope it works well straight out of the box, but if it hoovers its fire up working hard it will be interesting to see how that is dealt with.

 

2007's smokebox volume will be considerably bigger than on the original P2s due to the shorter boiler. It will be interesting to see if this damps the peaks of the individual blasts and produces a more even pull on the fire.

 

I would not attempt to directly compare Chapelon and Gresley, as their roles were so very different.

Chapelon was an exceptional researcher and designer, whose work aroused world-wide interest and influence. But he was not a CME, and there is no evidence that he sought a CME position or had the leadership and senior management skills needed by a CME.

Gresley, on the other hand, was an exceptional CME. Locomotive and rolling stock design is only a subset of a CME's responsibilities, which may sometimes be almost wholly delegated to subordinates or to external builders. Having said that, Gresley was heavily into design and produced some excellent examples. His impact beyond the LNER was probably mainly down to two factors. Firstly, his version of conjugated valve gear was noted and taken-up in the late 1920s by some overseas railways, notably in USA, Japan and Australia, but this interest fell away in the early 1930s. Secondly, the speed exploits of Flying Scotsman, Mallard, etc, would certainly have been widely noticed.

But in spite of his success as a designer, I wonder whether Gresley's greatest achievement was not in the design field at all, but in bringing together the loco/ rolling stock departments of the LNER's constituent companies into a single organisation, apparently without the factional infighting seen on the LMS.

That suggests that your Gresley book will be offering a fresh appraisal of the strengths and weaknesses of conjugated gear. I had formed the impression from your Thompson book that you thought Thompson was right to start phasing it out. Perhaps peacetime and wartime needs were different?

 

Edit: comment deleted.

When you're living in an occupied country, unless you actually join the resistance, and possibly even if you do, don't you carry on working in your normal job?

 

No doubt it does, but the Vichy regime only had any power in Vichy France. They had no power at all in the occupied northern and western France, where Chapelon would have been located. Even in Vichy France, they would have had no influence on the railways. As such the Vichy regime is utterly irrelevant.

https://en.wikipedia.org/wiki/Vichy_France

 

In wide ranging article on various subjects by L.A. Summers in Backtrack in May 2005 there is a single paragraph about Chapelon in which he criticizes the Colonel Rogers biography largely because the subject matter provided most of the information for the book and includes the following comment:

' I would like to know what Chapelon was doing during the Vichy period but neither Rogers nor anyone else has any information on this. Is it not unfair, I suggest, to ask why that is.''

This produced a strong response in August 2005 edition from John Van Riemsdijk who had been one of those instrumental in setting up the National Railway Museum. However, more relevant to this story is the fact that during the war he had served with the Special Operations Executive.

He considered the comments to be a ''vague smear'' about Chapelon and as for the alleged lack of information on this:

''That is complete rubbish. There are still people around who were in the SNCF during this period and I myself, and George Carpenter, have known others, as we have both known Chapelon himself. Moreover, there are hundreds of Chapelon's letters in various hands, including a block of over 400 written over 35 years to a very close friend, currently being prepared for publication by the French Association for the History of France's Railways, a very learned body with University status ( of which I 'admit' to being a member ) the proceedings of which includes two thick volumes of personal accounts of the SNCF in the Second World War. I had some (distant) contacts with SNCF personnel when I worked in the Special Operations Executive and followed these up early in 1946 when I formed lasting friendships with railwaymen of various grades. The conclusion to be drawn from all these sources is that, apart from a politically motivated minority, the prime loyalty was to France but some collaboration with the Germans was necessary to protect French lives. Chapelon continued working on post-war locomotive design and advising on motive power matters. He was a backroom boy, largely uninvolved in politics. However both he and Marc de Case, like numerous others, were investigated after the war for possible collaboration. Both these great engineers were freed of all charges.''

Interestingly Mr van Riemsdijk address is St Maximin in Southern France and the George Carpenter referred to had translated Chapelon's book 'La Locomotive a Vapeur' into English. Carpenter had fought in Normandy during the war and therefore like van Riemsdijk is highly unlikely to be sympathetic to those who were seen as collaborators.

Mr Summers was allowed the final word on the letters page of October 2005:

''I don't think it matters whether Chapelon was a collaborator or not, all I ask for is transparency about the facts''

and the main complaint seems to be that the sources are not available in the English language but should be. He also acknowledges that the choices of civilians under occupation was an unenviable one and that 'No one knows in advance how they will react in a given crisis and for some French people there was no choice'' and further that ''Mr van Riemsdijk makes the error of mistaking my criticism of the historiography of Chapelon with an attack on him''.

NOTE: My thanks to RAB3L , the reference should be to Marc de Caso although to be fair the letter as printed says de Case although I suspect the error was not down to the writer of the letter.

 

Marc de Caso

 

The status of Vichy France caused difficulties for both the Allies and Axis forces alike and extended to the French colonies worldwide. For instance the historian Mark Felton has recently put up a Youtube video about Japanese forces clashing with their Axis allies in French Indochina in 1940 because of how they had different perceptions of the status of the French colony.

A major example of the very difficult decisions that the British had to take centred around the 'neutral' French navy resulted in the very one sided battle of Mers-el-Kebir in Algeria:

https://www.bmmhs.org/mers-el-kebir-sinking-the-french-fleet/