Edward Thompson: Wartime C.M.E. Discussion

I took the original comment ("Nock must have misremembered") to simply be the suggestion of a possible failure of memory, nothing more. Failure of memory, especially over a long period, is quite common: I myself had a significant encounter with it during some historical investigations which I did (albeit in a different field; racecars, not railways), as described here. The especially surprising thing about that case was that several people all misremembered what had happened - until presented with photographic evidence that their memory had played them false!

I have no idea if Nock was accurate or not; and if he was, what the explanation is for the examination of that approach. But given the incidence of failures of memory (I have experienced it myself, in trying to remember past events in my early career - so I have seen it from both sides), that possibility has to be considered. And Nock's character doesn't come into it: it's not about him, really - this affects everyone.

Noel

 

I agree that long-term memory is fallible, I have had instances of it in my own career, and you have to be very careful with it in historical research. I do think, though that an account from an established historian such as Nock should not be dismissed without proof. It would indeed be interesting if any drawings of early Thompson proposals have survived. In fact it was Nock's account which got me interested in this, as I wondered what I would have done in Thompson's position. I look forward to reading Simon's chapter on Nock's involvement.

Tom makes some good points about the Maunsell U1 and N1 - especially the frame staying. If fitting an independent valve gear to the Gresley chassis would have required major alterations to the frames, then it might well have been impractical and too costly to be included in a normal overhaul.

I believe the N1 and U1 were designed with provision for fitting a separate valve gear if necessary, which seems to be what happened. My impression is that Maunsell ordered these 3 cylinder designs mainly to give Holcroft something interesting to do on the Southern, as he was being head hunted by Gresley. Holcroft was a clever man and if he had gone to work for Gresley, history would have been different, and perhaps we would not be discussing Thompson.

 

re the above and Simon's response that Nock must have mis-remembered .

I think it must be true - in essence at least , but it is a recollection by ET of a conversation with WAS. I doubt Nockie made an error -he was probably making notes at the time .
what is not mentioned is the context of the two engineers conversation . ….it could well have been one of those moments where two people are kicking ideas around to see what turned up .it may have been in a private house or hotel rather than the CMEs office , or over a meal .
I have no doubt ET would have rejected it if the scheme had been analysed.
Simon's comment about ET looking for simplification of design is another that I think must be wrong , because we know the LNER were hoping to improve the availability of the Pacifics. a modified valve gear must have looked a good cheap fix ATT., and was likely the subject that prompted the conversation .it is probable other gears were discussed at the same time . I wonder if Joy was mentioned ?

 

That puts it in perspective very well.

 

My Grandad was a Draughtsman at Doncaster into the 1930s, with Gresley spoken of in hallowed terms. No wrong could the man do.
Even though he spent the war mostly remetalling V2 big ends, round the clock as their workload increased. It wasdeemed an acceptable cost to their epic 20coach train haulage, those big ends were placed under stress they were never designed for; but they endured, and they hauled, and they hauled us to victory.
And as for Thompson (outraged voice) "he rebuilt Great Northern!!!
Was never going to win friends and influence people rebuilding what was regarded quite rightly by his people as a masterpiece!
A better wartime solution was suggested by Stanier, of improved metallurgy in the middle end, by his ideas(as in the nrm papers) I am convinced there were problems he had previously encountered, I thought it was his 3 cylinders, seeing the Caledonian quote this may be it.
Perhaps it was done out of desperation, like the Spitfires they were all working or being repaired, a fix would improve availability.

 

Yes Jim, I was being simplistic.

I wasn't going into the full nuances of locomotive design, only acknowledging that the Gresley drive all onto one axle plus three sets of walschaerts was possible and that the Bulleid Pacifics were an example of this.

Of course we could then have the discussion re cylinder inclination etc but I was just making a wider point that it was proved possible to do within the Gresley wheelbase.

 

Setting my stall out: I don't believe that there was ever any plan to inside Stephenson's valve gear to the Thompson Pacifics.

OS Nock's quote from above is at this point literally the only source, it has been mentioned it seems in just the one title of his and has never been mentioned in any other publication anywhere else.

I think if there were any truth to it, other writers would have jumped on the chance to criticise Thompson more on this point by introducing additional complication to the LNER Pacifics.

RE Equal length connecting rods - they allowed the three cylinder Pacifics of the Thompson type to have identical valve events and also be balanced equal angles to each other echoing that on the GWR 4 cylinders.

 

Exactly. I am not suggesting that Nock was being in any way heinous: but I question the accuracy of that statement. There's literally no other evidence or source to corroborate that.

I must speak to you on the above separately - very much a Team Lotus fan here and have a JPS Esprit to that effect!

I personally feel - if what has been posted above is accurate regarding the quotation in that volume - that Nock has misremembered. Nothing heinous - but inaccurate. Forgivable.

 

This is incredibly frustrating. Allow me to explain why.

Edward Thompson throughout his career looked to simplify the LNER's locomotives. Reducing number of cylinders, the complexity of valve gear, boiler manufacturing, use of piston valves and removal of Lentz gear (from the B12s), aiding maintenance...adding Stephenson valve gear is more complexity in a design.

In thirty years of working on the railways it would be incredibly out of character for Thompson to turn around - in the middle of a world war - and declare he wanted to put stephenson's valve gear into the P2 rebuilds, for instance, which were the impetus for the development of his Pacific designs.

It rather feels that you are concentrating on what you would do with a locomotive design, rather than what Edward Thompson is likely to have done in the context of his tenure as CME. If in a thirty year period he did not consider stephenson's valve gear once, was looking to reduce three cylinders to two (he even suggested rebuilding the Raven Pacifics of the A2 class in the 1930s with two cylinders to no avail) in any event, why would he suddenly turn around and suggest this in the middle of WW2? It is completely at odds with his behaviour, design ethos and recorded history.

Hence - I feel - Nock may have misremembered. He was certainly inaccurate on a number of other issues around Thompson, which I won't get into explicit detail here, but he was guilty of a number of "after the event" intimations of Thompson's behaviour despite there being ample evidence to the contrary.

 

A few things about the rebuilding of Great Northern (repeating myself somewhat)

- The A10s were poor on availability
- Great Northern was the oldest
- The Stanier/Cox report had suggested rebuilding with a third set of valve gear
- Thompson did not select Great Northern, L.A. Musgrave did
- The rebuilt engine was better than that it replaced by some way - it was in many ways a post war A4 Pacific (250lb boiler and frame setup together with the Thompson front end)
- The original was rebuilt during a pretty bloody war when availability on the LNER's Pacifics was pretty low

There were several suggestions - made by ES Cox as it happens and signed off on by Stanier

I don't believe it was done out of desperation, more to fix a known problem and to shape the LNER's engineering ethos going forwards.

 

Simon, with respect, you are missing the point.

 

Please explain it then.

 

Suspect this is all important. There are a whole lot of shades such a conversation could have been coming from, starting from "my lads say they can't fit Walschaerts in: they reckon a Stephenson implementation might be possible but the valve events would be dreadful" to "I told them to draw up an implementation of Stephensons to see how it would look" and dozens more besides. You do look at stupid ideas to confirm they are in fact still poor in changed circumstances, the important thing is to make sure they don't get off the drawing board.

 

Which probably wouldn't have helped very much, as according to Cook the main problem was lubrication.

 

And according to Bill Harvey, a lack of stiffness in the conn-rod big end cap.

 

Don't forget that some B16 4-6-0s were rebuilt under his direction still retaining three cylinders.

 

Good reminder, and fair point.

 

my thoughts re Nock/ET /Cox/WAS are these

ET was appointed in 1941
there were early consultations with WAS & Cox re availability of the large 3 cyl locos . Simon will have the date . C 1941/2 I guesss.
Nock publishes the comment between ET &WAS relating to valve gears in 1984 British Locos of the 20th C .that's the date of my copy anyway . the chapter "upheaval on the LNER " from page 105 gives OSN s account of conversation(s?) with ET and his own somewhat disapproving view of the discussion . there are hints that he did not tell all . OSN wrote an article in either TI or RM around 1959 in which he reports ETs proposed reduction and mechanical simplification of LNER types in more detail . crucially ET said he did not intend to radically alter existing large 3 cyl locos . we can assume that did not apply to new locos , as we know , his pacifics had 3 cyls. probably for the very good reason that a loco with 2 cyls giving 40000TE and 90 mph performance would not fit the loading gauge ,quite apart from being a rough rider. he may not have liked 3 cyls for a lot of reasons but he knew they had their place on the LNER and his future plans.

the conversation(s) with ET were at Thompsons invitation . as to the date , it must have been mid to late 1942 when ET had decided his loco policy ,and after the WAS/Cox episode.

Thompson must have known OSN would publish some or all of what took place . it seems logical that the comment re valve gears and Staniers reply must have pre dated this but it is reasonable to assume ET repeated it to OSN during this interview .

I simply do not believe OSN would not have taken notes on the conversation(s) between himself and ET , one of the most important CMEs in the country . he was a respected author and accurate note taking would have been an essential part of maintaining his credibility . I see absolutely no reason to believe he "mis-remembered" I believe he was using his own contemporaneous notes.

and , no , I do not believe there was ever a serious suggestion that ET would ever build a loco with a Stevenson middle cylinder.

 

Indeed so. However, if memory serves, weren't the B16s already pretty much on the loading gauge limit across the cylinders, and so larger cylinders wouldn't be possible? To make them into 2-cylinder machines would dramatically reduce their power.