Edward Thompson: Wartime C.M.E. Discussion

The GWR took on 925 locomotives, and bearing in mind the nature of the lines they absorbed one might guess that there were several hundred different types in there. But the GWR was able to institute a major programme of fitting standard parts and also a major programme of scrapping as much as they possibly could. It seems unlikely this would have been financially possible for the LNER.

Its interesting though that Gresley's priority for his drawing office seems to have been high profile new locomotives, whereas Collett had his draughtsmen working on tank engines to replace Victorian antiques and improving the maintainability of the absorbed stock. A huge majority of the absorbed stock - at least those which lasted - received GWR safety valves and whistles for example.

 

(I shall say the following through teeth gritted in admiration ...)

My understanding of Swindon practice is that through the 1920s and 1930s they developed a really sound understanding of locomotive availability. I don't just mean at a macro level - is it 75% or 78% this month? - but at a real micro, class-by-class level. Moreover, they worked towards having a standardised 80,000 miles between overhauls. Ostensibly, that is helpful in operational resource planning terms: if all your locos do 80,000 miles between overhauls, its easy to calculate how many you need to overhaul each year, and also to statistically measure your backlog against what you should be achieving. But also: once you set that expectation, deviation from it stands out like a sore thumb. If such and such a class only averages 60,000 miles, straight away you have something to get hold of: why is that? what is different about those locos?

From that, the Collett loco policy of the 1920s and 1930s starts to make more sense. The classes he designed may have appeared visually to be little more than updates of locos from two decades earlier, but unseen there were all sorts of little detail improvements, all working towards twin goals of higher mileage between overhauls and less variability in mileage. If my reading of Cook is correct, it became the practice on the GWR that Swindon called locos in for overhaul when they ascertained the planned mileage was up, rather than sheds sending them for overhaul when they met certain criteria of being worn out.

R.C. Bond wrote, in a 1953 paper, "The wide variations in mileage at which individual locomotives of the same class require attention in the works, to which reference has already been made, clearly preclude the use of average mileage between repairs as a satisfactory basis for determining when the locomotive should be sent to the works." That, in the eyes of KJ Cook, was an illogical statement. Provided there were the fundamentals of accuracy of repair and close tolerances, for which basis accuracy was necessary, then the mileage basis should become and was the only really logical basis on which to make the preliminary selection.

In that, I agree very much with Cook. From a casual perusal of Simon's data, it seems that there was a wide variability in loco mileage between overhauls on the LNER, and certainly there was on the SR. What is less clear is just how much those railways tried to understand why it was the case: if Bond is to be believed, the attitude may have been "that's just the way it is" rather than saying "no it really shouldn't be like that". (The SR might be excused in that their loco policy was very much "make do and mend" with steam in managed decline pretty much from the end of World War I with everything concentrated on electrification).

Coming to Thompson: as I read his policy (and allowance that he had to formulate that policy in tremendously difficult times), he had two inputs:

1. The loco availability was poor, particularly of some of the larger classes
2. A very large number of mostly elderly locos in a large number of small classes made the spares situation difficult.

From which his policy response was

1. Rebuild a few of the most problematic of the older locomotives, and design some more large locos of hopefully simpler, more robust design
2. Design a series of general purpose maid-of-all-work standard locos to replace the myriad different designs of mostly older, smaller locos.

So in engineering terms, was that the right response? For the second part, if it were wrong, then it was an error shared by Churchward and Riddles alike, who also set out to do likewise. For the former, the question is whether he could have done more - pace Collett and Cook - to have found out the reasons for low availability and designed it out incrementally. But I think that was probably a peacetime-only option: by the middle of the war, putting in place a wholly revised system of locomotive construction and maintenance was a decade or more too late, and drastic problems called for drastic measures.

Tom

 

Why not write to the A1SLT & make the point about the crank axle?

Gourvish pointed out (I think) that the 'Heavy General' was nearly the cost of a new loco so building a new locomotive, this meant that - rather as the Americans did building new rather than overhauling meant that you got an up to date machine made from all new material with the resultant operational cost savings.

 

One thought about the difference between K1 and L1 is that the K1 didn't have to carry about the weight of the tanks etc, which might have had some impact on the mechanical structure and stresses of the loco.

In that light - the Maunsell K class 2-6-4T had a reputation for rough riding, which was partly - but not wholly - down to the track. It is also notable that they were built "down to a weight", which in later years showed up in the U class moguls into which they were rebuilt, which had a reputation of being both a little under-boilered; and suffering weak frames in later years. I think Holcroft rues the fact that with the later series of U boats that were built straight off as 2-6-0s (not converted), the opportunity wasn't taken to address those points given more scope for increased weight.

Tom

 

But is that mileages between overhaul, or annual mileages? Because from the dataset we have access to, we can see that far, far too much has been made of "mileages between overhauls" when the reality is that annual mileage is by far more important.

Which is better: the Gresley P2 which did 100,000 miles between major overhauls (but took three years to attain that mileage), or the Thompson A2/2 on the same work which achieved 75,000 miles between overhauls but in the same three year period did 165,000 miles?

I have purposefully chosen that example as it's a real life one which exemplifies the issue with how previous writers have focused on only some bits of the evidence and have discarded others, rather than looking at the whole of the evidence available to them.

 

Rogers wrote a book in 1972 on the work of Chapelon.
Chapelon witnessed Cock of the North on Vitry and on line and was not impressed.
I guess that Rogers referring Chapelons impression of Gresley's masterpiece must have been written after his damnation of Thomson.
He had a viewpoint until he got wiser evidently.Wise tactic for a writer.
SBN 711002819 page 41 to 44

 

One of the features of Swindon practice seems to be about variation. In other words, if you have ten locos doing 75-85k miles between overhauls; and ten others doing 40-120k miles - both might average 80k but the consistency makes workshop management far simpler, because you can predict well in advance when each loco will be available and when not.

From a shedmaster’s point of view, the main concern is reliability. It’s no use saying “these locos on average do 80k miles” if you’ve drawn the short straw of the one that happens to break after 40k.

With regard whether miles per year or miles between overhauls is best: I think it is nuanced. You can decrease the time needed for a heavy overhaul by reform of workshop practice: that would result in less time in the works and therefore more days available for remunerative work, for reasons entirely unrelated to the qualities of the individual loco. The LMS I believe carried spare sets of frames for certain classes, which inevitably made overhaul times more efficient and got locos back into traffic quicker - but at the expense of building those spare frames. If nothing else it makes comparisons difficult.

Tom

 

Doesn't that depend on why the low mileage?
The principle Cook assumed was that overhaul costs are nearly constant no matter how many miles between them, and the prime expense in cost of ownership, so a locomotive that does 40,000 miles between overhauls costs you twice as much to run as one that does 80,000 miles between overhauls. So that is a critical number.

But equally if locomotives are forever in the shops having minor repairs then that means that you need more locomotives to run the services, which is capital expenditure, and the 1930s railways really disliked expanding the capital. And a lot of minor repairs may add up to the cost of one major repair.

 

Yes, that was the point. It is interesting looking at Townend's few pages on the L1s at Kings Cross. He is a bit of a diplomat, but it looks as though they did much better there than at Neasden but struggled with particular tasks like the sleeping car train empties up to Bounds Green and the heaviest commuter trains. On the latter they ended up double heading an L1 and a B1.

But I suppose such operating compromises are inevitable.

 

Didn't the L1s also knock themselves to bits on the GN out of Kings Cross too? They had very short lives, built just after nationalisation and all had gone by 62. Contrast this to the LMS ones, the first, Fowler tanks were built in the 1920s and lasted into 1966.

 

Withdrawal date is not a very good measure for locos at the end of steam. As an example, the last Adams O2 (built 1889-1896) was withdrawn in March 1967. The last BR Standard 4MT tank (built 1951-1956) lasted only four months longer.

Tom

 

The fact remains that the LMS 2-6-4Ts were vastly superior to the L1s

 

The O2s lasted so long because they got a niche job on the isle of Wight, see also the Beattie tanks in Cornwall.

And yes, the LMS tanks were massively better. One loco of Thompson's which I think we can agree on is the B1, in my opinion, probably the LNER s most useful engine and exactly what was needed at the time

 

Really odd comparison, and withdrawal dates of steam locos is a poor measure, given how the end of steam played out before 1968.

 

Maybe so - but withdrawal date doesn't tell you anything about that.

If you wanted to be pedantic though, there were O2s still in use on the mainland into the 1960s, well into their eighth decade - they weren't just used on the Isle of Wight. By contrast, many people consider the 9Fs to be the best of all the BR standards, but it didn't stop some of them being withdrawn only five years after being built. So the point remains - if you want to make a case against the L1s, it has to be stronger than "they were withdrawn at about the same time that mass withdrawal of steam was underway".

Tom

 

The 2-cylinder ones might have been, but what about the 3-cylinder ones?

There were Spanier types and Fairburn types too. What was their mileages and availability?

They may well have been better locos, or it’s a perception based on reputation.

So much in railway history and railway preservation feels like sitting between two football teams fans at times, rather than having an intelligent debate on actual engineering merit.

 

I'm sure that is indeed a factor. The L1 had a very large coal and water capacity - 4½ tons and 2630 gallons, compared with the 2000 gallons of the Maunsell K-class and the LMS and BR standard 2-6-4Ts. That is a lot of water to both slosh about and act as deadweight. I wonder whether the high water capacity was to suit specific duties or whether it was simply to use up the weight limit.

In the last years of steam, longevity seemed to depend largely on the varying progress of dieselisation and electrification in different areas. For LNER types, a key year seemed to be 1962, when numerous classes of GE/GN/GC origin became extinct, along with LNER standard classes that had been concentrated in those areas, including the L1. Steam lasted longer in the North-East and Scotland, so some vintage NER and NBR engines lasted until 1966/7.

In the earlier 1950s stages of modernisation, BR management appears to have decided on early elimination of certain classes, not just time-expired pre-grouping types but relatively modern types that were considered problematic. Included were the LMS Garratts and Fowler 7F 0-8-0s, and the LNER B17 4-6-0s and D49 4-4-0s - and from 1958 the J39-6-0s.

 

I think the 3-cylinder tanks were certainly fit for the job they were designed for.
The main problem on the LTSR lines was the dreadful quality of the water.
When locomotives had to be stopped every three months for some tube removal, outside the usual boiler washouts, and about 27cwt of scale and sludge was removed from said boilers each time, there was bound to be a knock on effect on availability.
Otherwise, a locomotive built successfully for a specific purpose.
Thorley's book 'A breath of steam' gives an insight into the peculiar problems of working out of Fenchurch Street.

Some of the L1 problems seem to have occurred due to the welded tanks.
This was not an unusual problem a the time.
The Merchant Navy tenders suffered from poor baffling and welds.
The BR standard tanks, particularly the 80000 series had similar problems.
I would guess that this was more a consequence of railway workshops and designers attempting to embrace newer technologies at the time, but not having enough experience in the UK to design and build such welded structures.
Maybe they should have looked a bit harder at progress on the other side of the Atlantic, where welding had been adopted for more applications over twenty years before?

 

It is accepted that Gresley was not only a successful CME but also an innovator hence it is to be expected that some of his projects would not be as successful as he had hoped. In that context the P2 could be seen as one such innovation and its presumed "failure" should not diminish Gresley's reputation as a successful CME. Had he had the availability of modern (computing) facilities there is little doubt that the P2 problem would have been resolved as no doubt the current A1SLT project will prove.

 

Bear in mind that the Eastern Region of the 1960s set about dieselisation by area hence the choice of East Anglia saw the replacement of elderly GER / GN designs by Classes 21 / 24 / 26 and 30 (later Class 31) Brush Type 2s. The first diesels were based at Ipswich, Stratford and Hornsey as the ER advanced from East Anglia to the Sheffield area with some early designs (i.e. Classes 21 / 26) transferring to Scotland and Class 24s transferring to the LMR and ER based at Cricklewood and Finsbury Park respectively.

In terms of steam traction note that the LMS Garratts were actually replaced by Standard Class 9s - before the introduction of diesel traction - but the rapid takeover by diesels tends to hide that fact. It must also be remembered that the Standard classes were introduced to both make good wartime losses as well as replace many of the older "problematic" classes; a case in point being the introduction of the 2-6-0 designs to replace many older 0-6-0 classes. IIRC the availability of both Stanier and ex-WD 2-8-0s also helped replace the "problematic" Fowler 7F 0-8-0s but whether the problems were design (i.e. mechanical) or staff (unwilling to operate them) is probably a matter of conjecture.