Hatfield Shed wrote: ↑Thu Sep 19, 2019 11:23 am
My fundamental objection derives from your clear misunderstanding of engineering praxis. The reason for new design is to secure improvement in performance.
That is not, strictly speaking, always true. Engineers and engineering are constrained by practical considerations such as time, materials, availability of staff, funding. It may be that improved performance is not attainable or desirable and what is actually required is improved reliability and availability.
Doing a job adequately for more time of the year than only doing the job incredibly well, for 2/3rds of the time of the former approach is not a good business approach.
The expense of the design work and tooling investment is only justifiable if the resulting product delivers more than that which it replaces. In brief here is the assessment of locomotive design output under Thompson's direction.
B1. Good low cost class 5 utility locomotive from a combination of proven major standard components.
O1. Good continuation of the established process of upgrading the O4 with later standard components.
K1. Good low cost smaller utility locomotive on the same principles as the B1.
All of these things are true but that is not the full extent of Thompson's work.
Pacifics. Abandoning the frame layout which Doncaster had devised for the first truly successful UK pacific design was a blunder, and there is no kinder word for it. The evidence for its success was plain: within the LNER's fleet, Stanier's adoption of it after the mediocre Princess, and Bulleid's work; all of it known to Thompson. The pacifics built to Thompson's pattern were mechanically hampered. The major components in the form of existing boilers and fireboxes, steam circuit, valves and cylinders, naturally enough worked well, but the maintenance charges resulting from the frame layout condemns this design.
The same old red herrings thrown out as usual. There is a fundamental misconception with the Pacifics and I can, happily, prove this.
The Thompson Pacifics were on a maintenance regime of preventative maintenance. The Gresley pacifics were on a "run to failure" regime.
Gresley Pacifics, and most large locomotives, were given targets for mileages between shopping. The Thompson Pacifics were not and this is seen in their increased visits to works.
Fundamentally though, this their reduced overall time in works and increased their actual ability to do work.
Availability is about how long a locomotive is ready for work and actually doing work. More visits to works for more preventative maintenance led to reduced overall time in works. The availabilty figures for WW2 that I have procured prove this. Gresley Pacifics spent longer in works with less overall visits. Which is better? The accountant would say the Thompson Pacific.
People have decried the mileages the Thompson Pacifics achieved between shopping without a basic understanding of what was being achieved. The main aim was not increase mileage between shopping but reduce overall time in works and maximize time actually doing work. Fundamentally - and I can prove this happily - Thompson Pacifics achieved that.
And wholly unnecessary, as Peppercorn's revised layout back to 'Gresley pattern' would swiftly prove post war.
The only difference between a Peppercorn A2 and a Thompson A2/3 is the length of the connecting rods and the position of the front bogie. What exactly in that is so fundamentally different?
One could argue cogently that your point here is somewhat undermined by the bizarre fitting of a single chimney to the A2s when first outshopped.
All that was required was the full implementation of the well proven Kylchap ejector to all the existing pacifics and V2s. An ideal wartime solution: cheap and it paid for itself. Thompson fully recognised the Kylchap ejector as highly effective, and this with a more rigorous maintenance scheme for the conjugating gear, which could not be eliminated under wartime conditions,was all that was required. Kylchap equipped A3 and A4 worked successfully to the end of steam, outlasting all the Thompson pacifics, which is all the information required to assess this project as a waste of (scarce) resources.
The problem here is that your understanding is flawed (yet again) as it is about context and the time of decision making.
Unless you are suggesting Edward Thompson was some kind of mystic with an ability to see a decade into the future at how kylchap equipped A3s and A4s were performing, you cannot possibly justify decrying decisions taken during WW2 by pointing out what happened in peacetime twenty years later.
The maintenance regime being more rigorous in WW2 for the conjugated valve gear was simply not possible. At all. The LNER lost 50,000 people to the war effort from maintenance and workshops. A huge number of people, a number from which the LNER never fully recovered. The conjugated valve gear locomotives' availability plummeted as the numbers of workmen available to do maintenance on them dropped.
The splitting of tasks between workshop/shed staff and drivers (oiling up valve gear opposed to greasing/lubricating the inside end of conjugated valve gear) also did not help.
Thompson inherited the LNER in 1941. It was 50,000 maintenance staff down. It had been bombed, repeatedly, and would continue to be. It was the most cash flow poor of all the railway companies. The availability of locomotives across the board was a big problem and the conjugated locomotives were proving to be suffering. I have the full availability statistics and you are welcome to access them if you so wish, and ask me nicely.
L1. Designed under wartime conditions, this should have been engineered to do the job despite the impact of austerity. The
weakness was poor mechanical detail design resulting in accelerated wear, poor reliability and high maintenance charges compared to similar locos for the same work. A retrograde step rather than improvement.
But fundamentally, this is NOT true. The prototype no.9000 did not exhibit the characteristics you describe and as such the overall design was not lacking.
The biggest issue was wartime austerity hangovers. Foundry capacity during WW2 was down 90% for the LNER due to manufacturing products such as armaments and vehicles for the war effort (and this was found to be a similar story on the other railways).
Parts that would have been cast were instead fabricated and/or welded construction.
The production L1s had fabricated axleboxes and welded tanks. Both of these were issues which in later life were partially resolved in different ways (in the axleboxes case, use of shims).
And fundamentally - again - increased visits to works but reduced overall time in works in a preventative maintenance approach compared to a "run to failure" regime is not a retrograde step. In fact the opposite is true.
The Peppercorn A1s managed to achieve a best of both worlds balance with only a few changes from the Thompson ethos (inclusion of roller bearings on some of them improved matters further).
Fundamentally, Peppercorn built 64 re-designed Pacific locomotives for which only 49 engines were largely identical, the A1s. The K1s were lightly modified versions of the Thompson K1/1 prototype and he continued building B1s, O1s and authorised more L1s.
Thompson was an extremely able administrator, for which his earlier career provides ample evidence. Had he stuck to his last, his period as CME would probably now be hailed generally a major success...
This is where we will have to disagree as I think Thompson's reign - was - a major success in light of the awful conditions he and his team worked under during WW2 - and this is born out by the 409 Thompson B1s, his O1s, K1s and L1s which worked up until dieselisation alongside the steam locomotives they were designed to complement.