Sir Nigel Gresley - The L.N.E.R.’s First C.M.E.

So I am approaching the finishing line for the book. At last!

My summing up is looking interesting. The topics covered and my current answers are:

Was Gresley’s conjugated gear his own? (Yes, it was)
Was conjugated valve gear any good? (Yes, albeit flawed - but not to the extent suggested)
Should he have gone to three cylinders for everything? (Yes - the output of his work put against the use of engine power document shows that there was a need for each class so treated and that some of them perform excellently)
Was he right to develop in streamlining? (Yes, the results of the high speed trains justify this)
Should he have standardised more? (Yes, with a but - finance and engineering development)
Is he one of Britain’s greatest locomotive engineers? (Undoubtedly - may be the greatest, but I admit bias)

Is there anything I have missed there?

 

What was his contribution to future development of steam locomotive design (think Bulleid and J.F. Harrison)
Was he a good manager in terms of supporting / encouraging his subordinates
Was his contribution to electrification valuable (e.g. delegating Raven as LNER electrification representative; designing EM1 26000 Tommy) despite closing the Shildon electrification network
Was his wagon / passenger coach designs long standing even beyond Thomson era (e.g. Gresley bogies adopted for EMU stock by BR in 1950s)

 

AFAIK the Gresley Bogie is in fact a Met-Camm design

 

We can acknowledge that those classes were needed to do jobs on the railway and that they did those jobs satisfactorily. Despite your post #1425 I'm not yet convinced about the trade-off between any advantages over otherwise-similar two-cylinder designs and the greater complexity. You mentioned more power within the loading gauge, but we're discussing medium-sized locos. Other railways fitted larger, more powerful, designs within the loading gauge.

I'm absolutely not wishing to be awkward but just to understand your reasoning.
Edit: deleted a superfluous word.

 

If we're simply talking about longevity I'm amazed his buffet cars found themselves in BR blue/grey.
https://www.steve-banks.org/prototype-and-traffic/364-lner-buffet-cars-61-6

 

Famous on the Waterloo-Exeter trains in the Warship era.

I'm looking forward to Simon's chapter on the Gresley pigeon vans which I think lasted until the 80s.

 

Chapter?

 

Why did the Gresley Buffet cars last so long?

 

I’m not sure why that’s such a surprise, when BR Mk1s lasted in front line (not charter) service for another 20 years.


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Is this a similarity to GWR low superheat, in that something that was justified when introduced, but continued when advancements meant it was no longer optimal?

 

Apart from design issues, there are wider management questions. Gresley appears to have done a good job in bringing together the mechanical engineering departments of the LNER constituent companies, avoiding the strife seen on the LMS. If he had failed in that onerous task, he might not have stayed in post to design and build the P2s and A4s.

How did he go about managing the inherited workshops and inherited locomotive fleets? My impression is that he delegated a fair amount of authority to the Area Mechanical Engineers. Pros and cons of that approach? Did it enable the best to be had from inherited assets, or did it delay desirable renewals and standardization?

 

Not quite right. Initially both the 01 and 03 Pacifics had 850 mm bogie wheels and one-side single brake shoes on to the coupled axles, being permitted to run up to 120 km/h. From 01.102 and 03.163 built in 1934, the bogie wheels were increased to 1000 mm diameter, the coupled wheels braked by a twin shoe Scheren (scissors) arrangement as used on the Bullied Pacifics, these being rated for 130 km/h.

The 01.10 and 03.10 of 1939/40 being 3-cylindered were considered better for running at higher speeds and were permitted to run up to 140 km/h, but there was a price to be paid in that the extra cylinder and mechanism increased to locos weight that resulted in them weighing in excess of 19 tonnes on the coupled axles. Even to achieve this the mild steel St34K for earlier boilers was substituted by a thinner material, St47K, an alloy steel that was to be found prone to cracking. This material was used on other classes from about 1935, including 01.10, 41, 50, 45 and 61. Many of these locos by 1945 that had not been 'shot-up' by allied aircraft or suffered other damage, were parked up with serious boiler defects. Several locos suffered boiler explosions including the case of 03.1046 in October 1958 at Wunsdorf (kreis Zossen) in East Germany.

 

So from my point of view I can see that the standardised approach he took was:

• Round topped boilers on older locos derived from his pool of boiler designs
• Use of conjugated gear and three cylinders, where possible reusing parts and drawings/designs across classes
• Conversion of locomotives right to left hand drive where reasonable

I think when you take each locomotive class on a case by case basis, you can find that there is a business case for the Gresley conjugated valve gear. The production of locomotives with (in theory), smoother torque, less hammer blow, but at or higher tractive efforts than comparative two cylinder designs are benefits. Were they realised in practice? I think on balance they were, but it feels like a law of diminishing returns as by the time Gresley passed, everything was in poor order (not of his making, of course!)

The only - and I mean only - exception is the P2s. It doesn't matter how much I keep trying to change tack on this, the fact that the Gresley Pacifics, V2s and later locos could and did do the work of the P2s (and heavier, actually, as times) on the same route as the Mikados reduces the necessity for them.

Gresley patented it, I am fairly sure...I need to check my facts. I know he had a patent for the articulation method in the United States, I have produced a copy of it in the appendixes of the book together with the conjugated valve gear patent.

 

So on checking my notes, they state that the "Gresley bogie" - all types - are derivations of the Spencer-Moulton design. The patent he had was specifically for articulation of bogies between coach bodies.

 

The P2s. I presume the remit was that a loco was needed to eliminate double-heading on the Edinburgh - Aberdeen route. To get the 21" diameter cylinders in the overall width of the loco they ended up being nearly 1-1/2" wider at that point than those of an A3. This left little or no scope for providing any flexibility in the rigid coupled wheelbase - hence the problems. The only way out, and Gresley wasn't ready for it in 1932, would be to increase the boiler pressure (meaning thicker plate and more weight), have smaller cylinders and increase the centres of the outside piston rods, thus permitting more side play on the leading and trailing coupled axles. Whether that would have been sufficient in practice is another matter.

 

Yes, but this becomes silly when we realise that under wartime conditions the A4 Pacifics in particular were pulling heavier and longer trains than that maximum stipulated load of the P2s.

Don't disagree with you on any of that but the fact we had the existing Pacifics, the W1 and the V2s doing virtually the same work undeterred in the Second World War makes the whole "P2s required to eliminate double heading" claim look silly. Or false, frankly.

 

Well, yes and no. If the wartime maintenance and availability looks sketchy does that suggest that due to wartime needs they were being thrashed beyond what was economical? Cook records that Collett upgraded Stars to Castles not to get extra work out of them but because, with the boilers not working so hard on the same duties, they would be more economical to maintain.

 

Silly? Or proven not to be needed in retrospect, but an experiment worth a try?

It's one thing to say that subsequent events proved that the A4s could do the job that the P2s were built for. But if in the 1930s all the A4s were fully occupied on express passenger work and you still had duties that needed half a dozen more big engines then building the P2s to fit a specialist niche isn't so silly. You didn't have the A4s to try on that duty (they were all fully occupied elsewhere) so if the duties existed, you needed six new large locos anyway, at which point there is little difference in cost between building six A4s or six P2s.

Having been constructed, they may have proved a big success, which would have been unknown had they not been tried. Or, as turned out to be the case, they were less than successful but could be subsequently rebuilt at significantly lower cost than a new engine into something more useful. Either way, constructing them found out something useful at fairly low marginal cost (assuming that, had they not been built, six A4s would instead have been constructed).

The LNER loco motive fleet was I believe somewhere over 6,000 locos, and they were building several hundred new ones per year. In that context, a small class of six locos - representing about 0.1% of the total loco stock - isn't especially extravagant in order to answer a question as to whether they would have been useful. In some ways a bit like a GWR 47xx - hindsight showed that they couldn't do much that a Castle couldn't also do, but worth the experiment if your capital build programme required a number of large locos to be built anyway.

Tom

 

German engineering appeared to screw-up really badly with that "improved" extra-strength steel which turned out to easily corrode and lead to boiler explosions - much more serious than the problems with wear on conjugated valve gears.

In Britain, the work in the 1920s of the "Bridge Stress Committee" had established the key role of hammer blow and that multi-cylinder locos typically had lower hammer-blow. Which I believe led to acceptance of higher axle-loads for multi-cylinder types, beginning with the Kings, Nelsons and Scots? But no similar leeway appears to have been allowed for multi-cylinder types in Germany?

 

I was speaking solely in relation to how the secondary evidence up to now has claimed it was about eliminating double heading. I don’t believe that it was intended for that, and I am sceptical that the secondary claims about the work of the P2s is truly reflective of how the LNER operated.