Edward Thompson: Wartime C.M.E. Discussion

Actually the notes I have on the presentation he gave shows that Spencer was quite defensive on the use of conjugated valve gear when others (including Cox) questioned him on its use.

If you look at the quotation provided you will see square brackets giving the context and it’s not Spencer making the criticisms.

Having read his paper at length I was left with the conclusion that I understood why Thompson would look to follow his own course without Spencer.

Yet somehow this has never quite come over in your views, Julian. Different approach needed?

Julian, it is entirely your prerogative to take offence at whatever you wish; the use of the word “monomania” however is a pretty ludicrous one and I don’t share your interpretation of Toms words there at all.

The reason it has thus been described is that you have focused solely on Bert Spencer. Who is incidental to the wider story I am writing on, I am afraid.

 

closely following Swindon and French practice so far as long lap travel valves where concerned - Pretty sure the French locos didn't have long lap valves - being compounds designed to run at circa 50% c/o they wouldn't need to. BTW I don't think that "long lap travel" is the right description, importantly they are long lap, and therefore they are long travel - I've never heard them described as long lap travel.

Bert Spencer wrote an article, presented to the Institution of Mechanical Engineers - no, Institution of Locomotive Engineers

Spencer is not on record as having responded directly to Hadfield or Cox’s points - he did reply to the points raised in the discussion

 

Excellent post. Where is that copied from? I am going off the notes available through the iMechE site.

Points noted down for editing. Most interesting!

 

The Development of L.N.E.R. Locomotive Design, 1923–1941
B. Spencer
Journal of the Institution of Locomotive Engineers, vol. 37, 197: pp. 164-243. , First Published May 1, 1947.

The Development of L.N.E.R. Locomotive Design
Journal of the Institution of Locomotive Engineers, vol. 37, 200: pp. 524-541. , First Published Nov 1, 1947.

 

Part of the Spencer comments, about Gresley considering in late 1940 whether to apply a gear based on the prototype No 461 to Pacifics and V2s, is also quoted in FAS Brown biography of Gresley.

Brown goes on to point out that No 461 was a slow-running locomotive. I recall, from the availability statistics that Simon published earlier in this thread, that the O2 2-8-0 had high availability, seeming not to suffer the wartime problems that were afflicting the conjugated gear engines used on faster passenger and mixed traffic duties.

Ref the suggestion of housing valve gear components in an "oil-tight casing", sounds like Oliver Bulleid had been consulted!

 

Noted. Many thanks!

 

As an aside to the 2 : 1 gear being good or bad, but the drive to the inside piston valves of the LMS "Duchesses" had no less than five additional pin joints over and above that of the outside Walschaerts gear driving them.

 

Hi Simon,

Might I suggest if you have not read Bert Spencer's 1947 paper in full then your chapter on Spencer when you quote the same paper is not particularly good research? And if you do subsequently read it in full and then do not appreciate all the niceties of the valve gear discussion, then you ought to state this, rather than presume you are qualified to give an opinion on these matters that are fundamental.

'Nokes' has given you the leads; if anything is not clear to you then this can be discussed and evaluated. I remain to be persuaded that you have the slightest idea about the niceties of valve gear design, which is fundamental to much of your own approach to Thompson etc.

Question for you... How much lap and lead and travel do you think the A1s ought to have had, and why was the Thompson B1 smokebox draughting less than optimal? What makes you think E S Cox was qualified to give an assessment on valve gears?

With best wishes for the New Year,

Julian

 

So Cox was not qualified to give an assessment on valve gears, but you are. Why? Just because you say so does not convince me one bit. Lets hear some form of evidence from you instead of you constantly knocking Simon's research. We would be far more convinced by your criticisms if you cared to back them up with sound arguement which you seem reluctant to give us. Lets face it there is no perfect valve gear - they all have their strengths and weaknesses. As I see it Simon is not saying anyone it right or wrong in their design, rather he is seeking to understand the circumstances which dictated a different approach to the subject in the 1920/30s and the 1940s. What is wrong with that?

Peter (who is gave up trying to get his head around the dark arts of valve gears ages ago).

 

Happy new year everyone.

I think there is a basic, fundamental, misunderstanding in what my book is actually about, and what I am actually writing about.

I am not a valve gear engineer. I have been neither trying to write on, or fully understand the niceties of, valve gear.

What I have been trying to do is assess what information we have, and whether Thompson’s decision making was informed and robust.

My views on valve gear are largely irrelevant to the questions which are always posed on Thompson - which as we know, frame him as something of a pantomime villain at times.

It’s not a competition, or a deep dive into the abyss or what valve gear was superior - it is, emphatically, about whether Thompson was justified to take a different approach and why he did so.

You can do this by observing:

- availability records (time spent in workshops, out of action, etc)
- engine cards
- board minutes
- contemporary news articles
- individual experiences (those who were there at the time if possible)

From my point of view (and I feel I have been consistent in this) I am only interested in looking at the CMEs role as it actually is - policy developing role, not a detail orientated one.

Good CMEs delegate and produce machines which give good returns in performance against their investment.

WW2 however changes the situation and how much a CME can decide to do. Thompson and Bulleid both found ways to create designs they felt were needed or wanted.

Both of these men stepped away from conjugated valve gear entirely. Only one is pilloried for it.

At the end of the day, I am not writing about the justifications for or against conjugated valve gear, though the evidence I have collated will show to some the valve gear in a different light.

I am writing about whether Thompson’s decisions were justified in light of the wide range of evidence available, and whether the circumstances permitted those changes.

The wider evidence outside of Bert Spencer’s opinion stacks up for Thompson’s views, not against him.

In any event - I think I can say happily that I have proved beyond reasonable doubt that Thompson wasn’t acting out or spite or maliciously, based on the records provided.

 

Bravo!

 

{A ' like' just wasn't enough…}

Very well put.

Noel

 

Much appreciated. Thank you Noel. I try!

 

Oh, one other thought:

"The difference between theory and practise is even bigger in practise than it is in theory." (Often attributed to Yogi Berra, but it seems to be older)

I'm an electrical engineer, not a mechanical one (unlike my wife and son), but the two fields have enough in common that I'm pretty sure that nobody really understands steam locomotive valve design to the same level as Spencer and Cox, unless they have extensive experience in designing steam locomotive valves. In part, for all that's written down, there will be a lot that isn't. Also, people aren't perfect, so perhaps both are wrong.

For me, the two apparently disagree; and I'll never know enough to have a useful thought as to which is correct (if either). All we can do, I think, is record that they differ, summarize their reasons (to the extent they wrote them down, or they can be inferred - e.g. the maintenance issues related to the war-time manpower situation), and provide references to remaining documents which give more details.

Noel

 

Given that this thread is adjacent to the 'Leaders' thread, I find myself wondering whether Bulleid, had he stayed with the LNER, would have rebuilt Gresley's locomotives with sleeve valves...

 

I think @Jamessquared's emphasis on management is important; somehow, I don't see the LNER board being willing or able to provide the resources for that kind of experimentation.

 

Hi Simon,

Thank you for your reply. I was expecting something more vitriolic!

My personal opinion is that if you have a chapter on Spencer you need to have read all of his paper of 1947 in full - which was to a meeting of all the high and mighty - and he had then to answer lots of questions from his peers - also recorded. I read it quite a few years ago, same as I read all of Holcroft's papers, and much else besides.

Cox's Report to Thompson was based on information provided by Spencer. You can see this from Spencer's 1947 paper and the Cox Report. Once Spencer had done this for Cox, Thompson got rid of him from Doncaster. Well, lets be less opinionated on my part - let us say instead the timing is strangely coincidental.

As I see it, a lot of the Thompson debate does revolve around valve gears. The E S Cox Report is just one example. The later rebuilding of The Great Northern can only really be justified on an argument about valve gears - doing away with the conjugated gear, and substituting 3 sets of valve gear with equal length connecting rods because Thompson (I would argue misplaced) thought equal connecting rod lengths would give better valve events. And this occurred in 1946!

Thompson's successor (after Peppercorn), Cook, found a very simple cheap way of improving Gresley conjugated valve gear locos. If Thompson had been as good an engineer as Cook, he ought to have done what Cook realised needing doing. If Gresley had listened to Spencer in 1922, a lot of these problems would have been avoided anyway. If Thompson and Cox had listened to or sought the advice of Holcroft, he could also have provided input as the leading expert on conjugated valve gear in the UK, but for reasons that are inexplicable, Holcroft was never consulted - though he devoted a paper that subsequently addressed, inter alia, a critique of the Gresley conjugated gear - exactly the same as Spencer did in his 1947 paper!

The papers were all presented and published over 70 years ago - were all discussed by an audience of peers, and have been available to those who wish to read them for a considerable number of years.

Those of us who have read the papers by Holcroft and Spencer, and the subsequent discussion also printed at the time at these meetings, cannot be in any doubt that these are very valuable to any discussion on what Thompson did (and what Gresley did). Cook's autobiography sort of completes the picture as to what he did when he went to Doncaster.

This is why I consider Cox's report as biased and poor. It is quite a funny thing about Cox - he was a 'negative' personality in out look; highly critical of everyone else. Very rarely positive, and apt to claim credit for things that were not his own contribution. I think we have seen some evidence of this on other threads.

Cheers,

Julian

 

Not really. Surely the purpose of rebuilding the locomotive was to get a cheap prototype for *all* the proposed design changes. And more even valve events are by no means the only consequence of equal length rods.

It wasn't Thompson's job to design a better big end. It was Thompson's job to order that it should be done. AIUI the records show that both Gresley and Thompson had initiated big end redesigns - and the results weren't good enough. What Cook was able to do was to bring in better fundamental design. You can certainly argue that both Thompson and Gresley should have ordered their staff to look outside their own experience - Cook tells us that the inspiration for the GW bearing lubrication redesign came from looking at machine tools. The contrast seems to be that in the 30s both the GWR and the LNER were having trouble with big ends, but Collett had his staff go right back to first principles and fix the problems, while Gresley had his staff designing new locomotives.

 

Could Julian possibly give us a summary of the conclusions about valve gears at the time from all that discussion?

Given the poor availability under wartime conditions, at least partly due to inadequate maintenance of the Gresley gear, and the Cox/Stanier paper rightly or wrongly making a strong case against perpetuation of the Gresley gear in future, was Thompson's policy for future construction (three separate sets of valve gear for large locos and two cylinders for the rest) a poor choice? Were serious suggestions made of adopting a different form of conjugated valve gear? (And if so why might Peppercorn have stuck with three sets, albeit abandoning equal length connecting rods?)

And could Simon please remind us what Thompson did to improve things in the short term?

 

See that Hornby are adding Thompson Pacifics to their 2020 Range. I wonder how much influence this thread and Simons persistence in raising the profile of Thompson has had in Hornbys thinking?