Edward Thompson: Wartime C.M.E. Discussion

The Staniers were the latest (slightly) of the quoted examples, the others being of an earlier time. Stanier built only a few specifically for the LTS where fast acceleration from numerous stops was required. They were "over-cylindered" in relation to their boiler but the boiler could be brought round during the constant periods of coasting, slowing and waiting. All his other 2-6-4 tanks were 2-cyliners, just like those of Fowler and Fairbairn

 

As an engineer, even more irritating is having to repeat my points because someone doesn't seem to understand what I'm trying to say. Still, you're right - minds have been made up and nothing I say will change that.

 

Sorry, obviously the rest of is are too thick to understand....
Are you trying to say Thompson was a rotter because Gresley's gear was the best thing ever? If so, why did no one else in the world replicate it in large numbers (and no one on smaller locos)? Why did Peppercorn not use it, was he part of the anti-Gresley conspiracy? I assume you acknowledge that Thompson couldn't use post-war knowledge to solve his wartime problem? I also hope you realise that in 1942 saying something worked fine in 1935 was irrelevant - they had to work the trains then! It was widely predicted by then that post-war would be quite different from pre-war.
No one is saying Gresley was useless, everyone is saying he was a superlative giant. His achievements prove this beyond doubt. Nor can he be blamed for problems which showed up after his death.
No one is saying Thompson was the greatest CME ever, or even amongst the greats. We are just saying he wasn't completely useless, his decision to stop building new locos with the valve gear made perfect sense at the time, and he designed some (very?) good locos - the ones hid railway needed at the time. He also designed some with silly features, and which were not handsome (although attractive to some!).
The decision to rebuild 4470 was foolish and, if deliberate or if he could have chosen another, certainly looked vindictive (even if it wasn't). He was obviously insensitive at the very least. But then no one is saying they want him round for tea - the question is why is he the great stinker?
Stanier (or his people anyway) rebuilt Royal Scot. Why no condemnation? Surely because it produced a handsome and improved loco. But that is post hoc analysis - in both cases the designer *thought* they were improving a loco. Thompson's rebuild wasn't as good as Stanier's - don't think anyone ever said it was - but that doesn't make the decision to rebuild black or white.
What I am saying is that:
1. there is a lot of hindsight being applied to judging ET's designs and decisions, which is not applied in the same way to other CME's (Bulleid!)
2. why is Thompson alone subjected to outrage for rebuilding a predecessor's loco(s), but others (Stanier, Deeley, Wordsell, Urie, Wainwright, Maunsell....) are not?
3.

 

Please go back to post 712 and read it. If you don't understand what I'm trying to say, fair enough. As to all the stuff above, perhaps you could read the rest of my posts which are listed a page or so up. You should find my views on all the questions you've asked there.

I appear to be in a minority so I'll shut up and let the revisionism continue unabated.

 

I think the term "you can lead a horse to water, but you can't make it drink" applies - this is a thread I've chosen not to comment essentially because the mind has been made up of the primary revisionist and life is too short to rise to such bait. Don't beat yourself up about it and I for one have learned stuff from your postings.

 

I don't disagree with your sentiments generally, but I think the reason that Gresley gear was not used in "large numbers" elsewhere, is more to do with the lack of enthusiasm for three-cylinder machines elsewhere, excluding compounds. Where three-cylinder simples were used, I suspect it would not have occurred to many of the railways which ordered them to specify, or insist on, a separate valve gear for the middle cylinder if they could get away with external gear, and Gresley valve gear appears to have been adopted on locos in a number of countries pre-war. On some locos though, it was not, and on some classes e.g. the metre gauge Thai Baldwin Pacifics (which were fairly small locos), it seems to have been discontinued in later batches. The 2:1 lever on these locos was to the rear of the cylinders, where it was not as accessible as putting the levers ahead of the cylinders. and Ramaer suggests maintenance may have been an issue. Experience of other countries would be a useful area to explore in the book though.

Changing the subject, the Chinese re-named the FD Class during the Cultural Revolution, as the FX 反修 "fan xiu" class, meaning "anti-revisionism", although I don't think they were targeting supporters of Thompson.

 

Ill in bed still so please forgive me if the latter makes little sense.

It's funny how both "sides" of the debate say exactly the same thing at an impasse.

The mind is made up, there's no room for manoeuvre.

I've never at any point denied Thompsons failings. He clearly upset a number of people in office - he clearly also had different sides to his personality.

Locomotives? Clearly some good ones and also rans like any other.

I'm not asking for a wholesale revision of Thompsons character or history. I'm asking if the current thinking is fair and clearly it hasn't been entirely fair on a number of points.

Here is where the fairness in a debate kicks in and whereas one side sticks solidly to the seemingly Gresley Society approved version of events, others are able to see there's more to this story than meets the eye.

Case in point: Coxs report. OS Nock repeatedly dismisses it as not saying much about the conjugated valve gear despite never reading it.

ES Cox, who wrote the report, did not pull his punches in the report yet accuses Thompson of using it in a Machiavellian campaign.

So are the views of Nock and Cox consistent with the report and what Thompson did subsequently?

Everyone throws out the word revisionist at times. Yes maybe it is but perhaps it wasn't reported well in the first instance and subsequently.

And surely, if there's a possibility, however small, that the established thinking is wrong, it's good to revisit it calmly and establish why that is?

 

Well Thompson was well known as an admirer of Stanier and I've made the point a number of times that if you look at Staniers Princess design (and early drafts of the 3 cylinder version) you can see Thompsons engineering ethos later on.

Compare the A1/1 to 6201 as built with the stovepipe chimney and I challenge you to find much of a difference in the overall layout.

Aesthetically very similar layouts: in reality of course mechanically very different.

The point I'm making is that Thompson made a big change in terms of three sets of valve gear, and looked to Staniers work most likely.

Peppercorn then changed the bogie arrangement and the coupling rod lengths but the three sets of valve gear remained.

 

I have just done so. Your criticisms of the Stanier/Cox report seem very fair, with one exception: the lack of explicit mention of wartime conditions is hardly surprising when all concerned were all too well aware that there was a war on. The question being addressed was what the LNER should do at that time (with a war on) about certain locos that had become unreliable. Yes Cox could have asked a few more questions about what had changed since the war started and whether locos based at some depots were worse than locos based at other depots; but he didn't, and Thompson and the LNER Board proceeded on the basis of the advice that they got from experts.

S.A.C. Martin has been looking for and at evidence with the intention of helping anyone with an interest to assess that evidence and draw their own conclusions as to why Thompson did what he did and how far he was right or wrong in doing it. That is "revisionist" only insofar as it departs from the previous received wisdom, which condemned Thompson as having done mostly the wrong things and just out of spite against Gresley. There may still be some truth in that, but power to S.A.C. Martin's elbow in seeking a balanced view -- neither wholly pro-Thompson nor wholly anti-Thompson. And certainly not with his mind made up: unlike some here he seems very open to any fresh evidence as and when it can be found. (And best wishes for getting over the flu or whatever it is!)

 

All the above has been said before and discussed before. I'm afraid I've spent too many hours on this subject. Publish your book and lets see what the wider railway enthusiast world thinks of it.

 

Hi Simon,

re your 3 sets of valve gear...

I throw in the following link from valve gear expert Don Ashton

http://www.donashton.co.uk/html/peppercorn_a1.html

Be careful in noting where Don has corrected the errors in the original inside gear as used by Peppercorn, as opposed to where Don points out these original errors.

Don found that the inside cylinders of the Peppercorn A1s were overworking, just as could happen with the Gresley conjugated gear. I do not know if the Peppercorn shorter radius rod and more tightly curved expansion link for the inside cylinder gear was taken from the Thompson gear. Someone else with access to the Thompson drawings will have to confirm this.

Assuming for the moment that the Thompson inside valvegear contained the same problems as the Peppercorn gear, then both Thompson and Peppercorn did not resolve fully the potential for the middle cylinder overworking with the Gresley gear.

Bearing in mind that the LNER valve gear expert Bert Spencer was moved from Doncaster by Thompson, I personally cannot see how Thompson could have benefitted from his knowledge and help. (One of Peppercorn's first acts was to get Spencer back to the Doncaster Drawing Office).

It seems to me that if you are going to add a third set of valve gear you ought to make sure it produces much better valve events than the old gear.

It would also explain why the middle big end bearing continued to cause problems on the rebuilt and new locos until K.J. Cook took charge.

Cheers,
Julian

 

With my limited understanding of Don Ashton's pages it seems to me that the irregularities in the valve events for the Peppercorn are minor compared to those of many other classes. He certainly is less than enthusiastic about the conjugation gear. Reading his text carefully I don't believe he specifically states that the valve events on the A1 are superior to the A4, but to my mind its implied. Maybe he's never done the detailed analysis?

It certainly seems excessive to ascribe the big end problems solely to the valve gear, and indeed the Cox/Stanier report doesn't do so. The big end problems were surely principally down to the simple fact that the big end just wasn't man enough for the job (no great slight on the LNER - we should note that the original King big end wasn't really good enough either). If the inside big end is transmitting more power than the outside ones then you have to uprate it to cope with the loads its experiencing. Easier for me to say than for them to do of course! Still it was managed in the end.

 

One thing I have never understood in the controversy about the conjugated gear is the way the outputs from the outside cylinders also varied a lot. (See F A S Brown/indicator tests/Humorist) Would the engineers care to comment please?

 

Hi Beckford,

Bert Spencer refers to the indicator tests of A3 2751 Humorist in his paper to the Inst LE in 1947 on LNER loco design 1923-41. I presume this is where F. Brown sourced his information.

I do not have the full proceedings, but a summary of the paper and the subsequent discussion at Manchester on 23rd April 1947 appears here

http://www.steamindex.com/jile/jile37.htm#222

I have not heard of the outside cylinder's work being affected by the conjugated gear, and it is not commented upon by Bert Spencer. The indicator diagrams were appendixed to his paper. I cannot see how the outside cylinders would be affected.

There are numerous comments on the Gresley conjugated gear and the Thompson rebuilds, but no criticism of Thompson by Bert Spencer to such an august organisation (which is exactly as one would expect). It provides an interesting contemporary 'snapshot' of the views of those who took part in the discussion, shortly after Thompson had retired but of course was still 'around'.

Rather than quote extracts from secondary sources such as books, I think it is always important to go back to the original primary source material, albeit in the above link a summary.

Cheers,
Julian

 

Julian, just picked out a section from Bert Spencer's address there. It makes interesting reading, particularly the "design of fewer types" comment near the end.

 

You are quite right: Brown is quoting Spencer.

He then goes on to show a small table:

Speed MPH Outside Cylinder hp Middle Cylinder hp Outside Cylinder hp
57 460 558 518
63 394 547 472
75 402 585 480

Edit: for some reason the table just won't appear correctly - apologies

 

Hi Beckford,

I think the actual indicator diagrams and valve events figures obtained would be the only way of making an informed assessment. One outside cylinder developing more HP could be due to all sorts of factors eg re-bored to a larger size. The HP isnt itself the only factor when considering say effect on bearings, as this will depend on such things as clearance volume, and degree of compression. One would need to know a lot more about the indicator trials themselves and the exact condition of Humorist.

I have mentioned previously that one of the Holcroft conjugated SECR engines when indicator tested on the road provided perfect diagrams.

Simon makes a further comment about 'standardisation' mentioned in the Spencer paper discussion. By the time Thompson had retired he had little effect on 'standardisation'. Only the original 10 B1s were in service, with the outside orders for them just starting to come through. At the end of WW2, Thompson's standardisation plan had made no effect whatsoever. He had run out of time.

Bert Spencer does suggest in one of his replies that the P2s ought to have been tried on the ECML before being re-built. You can read into that what you will.

Just one additional point, on the Peppercorn A1s, Don Ashton found that the auxillary reach rod levers were shown on the drawing the wrong way round/on the wrong ends. By correcting this error and a few other tweaks he was able to get decent valve events for outside and inside, but not without this alteration. Again, it would be interesting to note if this error also accured in Thompson's 3 sets of gear.

Cheers,
Julian

 

One last comment from me on this: Brown goes on to quote Holcroft as saying he had observed on the SR the issue of the middle cylinder developing more horsepower than the outside ones - "a well marked characteristic".

 

Well that's not true, with respect, Julian. Over 400 B1s built, 70+ L1s, 70+ K1s as the main standard classes after he retired.

Withdrawn from service from 1942 onwards - as planned - a multitude of pre grouping 4-4-2s, 4-6-0s and smaller 4-4-0s.

Thompsons legacy was for the LNER to continue with his standardisation plan: Peppercorn made two big changes to the planned A1 and A2s and minor changes to the K1 but everything else continued as planned - B1s, O4/8s and O1s being built well into the BR era.

Smaller classes continued to be withdrawn as and when right up to the end of steam.

All six engines were tried out on the ECML in their formative years. Some commendable running by 2001 and 2002 in particular recorded out of KX.

When rebuilt 2005 was tested against the remaining P2s for a year on the same route before authorisation to rebuild the rest was taken.

 

That seems to do Thompson a disservice. He introduced a mixed traffic class that ultimately had 400+ members - if that is not having a profound effect on standardisation, I don't know what is. The fact that many were built after he retired is immaterial: future CME's evidently saw fit to continue building his design. In that he is hardly alone - many other notable CME's had their designs continued by successors, but the credit for the design surely lies with the person who put it in place.

Railways have annual capital programmes and workshop capacity, that means even if the ultimate intention is introduction of a large single class, there is only a certain rate that they can be built, both because of limited workshop capacity and the need to use even the old, non-standard designs, up to the point where further repair and use is uneconomic. It would be more odd, and not the mark of a good manager cognisant with both traffic and financial imperatives, had such a large class all been introduced very quickly, rather than over a long planned construction phase.

Tom