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

Here.....

 

I was asked to give an impromptu version of the my talk for the Gresley Society at the weekend, and ended up giving the talk to a range of its members, including society president John Cameron and one of Gresley’s grandsons, and great-grand daughters.

Although I had a bout of nerves early doors, I managed to get through to the end, presenting all of the data and fielding questions.

As a life long Gresley enthusiast and member of the society, it was an honour to present my research to the society. I did not expect to be able to present research twice in one lifetime, having done this previously in 2019 when presenting my Edward Thompson research to the society.

 

I’m going to give my two cents here.

I don’t go as far as some in saying that Gresley was “overrated” or “not a good CME” because I think it would be ludicrous to say that. But I do think that Gresley became a little too lost in his own ideas for his own good.

His three cylinder conjugated valve-gear was not a rousing success in my opinion. First of all, he used it excessively on designs which there was no benefit to using three cylinders instead of two, such as the O2 and K3. I’m sure someone could actually post the maintenance and availability statistics, but I’m fairly sure that these locomotives cost more over their lifetime than would have otherwise. Second of all, it wasn’t well designed. Sure, it worked well enough if maintenance was kept up, but if the locomotives were worked too hard or maintenance was neglected, it didn’t take long for its issues to show themselves.

It was an overly fragile design, and this was proved essentially every time it was used overseas; Australia, South Africa, the US, where it was either a maintenance headache or simply was a complete disaster in terms of functioning, with many non-UK locomotives with Gresley valve gear being rebuilt later with three separate sets of valve gear or some other alternative. Gresley essentially handicapped himself by sticking to this design principle which was faulty from the beginning.

And also, I’m not sure if it’s entirely correct to say Gresley was ahead of his time when the Deutsche Reichsbahn Baureihe 05 essentially beat Mallard to the chase by two years, with no special preparations, doing it on a flat track, and not damaging itself in the process. It’s not like Gresley was a pioneer when it comes to streamlining, it was being done on the continent for decades before. The Bayerische S 2/6 applied air-smoothing techniques, and reached a speed of 154.5 km/h as early as 1907. I know this is primarily a British forum, but I think Continental (particularly German) railway engineering during the steam age is often ignored or unknown.

 

Small boys with cold knees,no watches and loco spotting note books also need heroes when old and cold to the bone.
You did not mention Gresleys double swing link pony truck ?

 

Oh I’m definitely aware of the pony truck and the multiple derailments it caused during and after WW2, but I didn’t want to go on for too long.

 

I think on balance that’s unfair. He certainly ploughed his own furrow in a way that very few other CMEs did.

I have to leave some things for my book, but the O2 and K3 are actually some of Gresley's rousing successes. My research is basically indicating that the issues of the conjugated valve gear are in relation to speed and maintenance. As an aside I would point out, with confidence, that his smaller three cylinder locomotives, including the V1s, are showing in the data I have to be very resilient to the wartime issues.

Hmmm. I think we need to be careful here. The conjugated valve gear did present its own issues, for sure. However I am 99% confident that the issues only drastically manifested when running at high speed for extended periods of time. And it can’t have been that bad mechanically, because the high speed trains in relation to the A4s had absurd levels of punctuality and completion rates. Absurd good, not bad!

No other railway in the world was running a streamlined train like the Jubilee, Coronation or West Riding. In streamlining the entire train (and doing so through scientific processes rather just through design ideas) he was definitely ahead of his time when it came to high speed intercity trains. And they worked. He was pushing for upgrades in signalling and track infrastructure prior to the second role war to improve this further (remove double blocking of signal sections).

The German O5s comprised three examples of a steam locomotive and they were not in everyday service. Success? No. One off speed record? Yes. Did they pull a daily high speed service in any way? No.

The A4 class worked daily high speed trains from September 1935 to the start of the war and on resumption of peacetime ran new versions of the high speed services, albeit without the streamlined trains.

I’m not unaware of German engineering and the O5s in isolation are impressive but it is accurate to say they didn’t run the services the LNER did.

Re the swing link pony truck - no doubt, it was not up to the task for the largest locomotives running at higher speeds on less than ideal track, in particular in Scotland.

 

Fair enough that the conjugated gear on those classes didn't cause much trouble. But that doesn't address whether designing those classes with three-cylinders was justified at all. Given how few similar locos in Britain or elsewhere had three cylinders, it does smack of Gresley having a large bee in his bonnet.

 

There's a considerable section of "Locomotive Adventure" by Holcroft devoted to comparative trials between 2- and 3-cylinder N / N1 moguls on the SR, which were slightly smaller but broadly comparable to a K3. The gist as I recall (I'm away from references) was that the two cylinder locos were better in coal and water consumption up to trains of around 40 wagons; beyond which the three cylinder versions performed better - i.e. at the highest steaming rates. I seem to recall a lot of the reason for that was ascribed to a more even draft resulting in less fire throwing at high power output.

There's no info, as I recall, about comparative construction or maintenance costs, though in the end the SECR / SR only built 6 of the three cylinder N1s, but 80 of the two cylinder Ns. That may have been because the heavy trains weren't there in sufficient numbers to justify the three cylinder type (supposition in my part).

Tom

 

And I think you could argue, if there was evidence, that Gresley’s approach was wrong and at odds with everyone else around him.

Certainly, when I was researching the Thompson material, that seemed to be the case. But going through the data I think the overall debate is far, far more nuanced than that, and it would be a disservice to the excellence of some of Gresley’s most successful designs - the O2s, the V1s, the K3s, the V2s and the Pacifics to say that having three cylinders across his fleet with conjugated valve gear was wrong.

I think there’s scope for Thompson being entirely correct to want to go to two cylinders and also Gresley providing the LNER with locomotives in peacetime which were more than capable of doing the jobs required, moreover, being of sufficient value that in Thompson’s “non standard, to be maintained” group they are mostly Gresley’s conjugated valve gear classes and undoubtedly his most successful ones.

 

Please enjoy
https://en.wikipedia.org/wiki/Henschel-Wegmann_Train

Reichbahn went the high speed diesel way.

 

The fact that Gresley's designs were more than capable of doing the jobs required is of course important, but it leaves out whether simpler 2-cylinder designs (for the smaller locos) would have been as capable, or nearly as capable, while being a bit cheaper to build, to operate and (possibly*) to overhaul.
* There would be more bits to overhaul on the 3-cylinder loco, but some of them would have been subject to lower stresses in use so might not need so much work.

 

One loco plus four coaches, for a two hour journey. Nowhere near comparable to the Silver Jubilee or Coronation, IMO. Sceptical you can compare.

 

And you don't have a bee in yours?

 

I'm with you on this Simon. There is no comparison.

 

It's a fair question, for sure. The overall feeling I am getting is that the Gresley locos in all but maybe a few instances is on parity with some two cylinder designs and in fact offering a better overall package.

I still maintain Thompson was entirely right with his choice of standard and non standard to be maintained locos, though.

 

I think perhaps expediency. Fifty of the Ns were built from Woolwich 2 cylinder ‘kits of parts’
purchased at a bargain price.

The N boiler was also a compromise i.e smaller than the preferred original design due to weight
constraints on the 2-6-4 tanks ( and I suspect loading gauge with the water tanks ) . Not wishing
to have two barrel sizes the smaller design was accepted as standard.

Michael Rowe

 

Something that is bothering me, but is likely to cause a hoo hah...

I am not at all convinced of the argument that Holcroft "helped Gresley develop his valve gear".

I've gone over the primary evidence - Gresley's patent and Holcroft's one, and I cannot reconcile that they are similar in anything other than the principle of derived motion onto the middle cylinder of a three cylinder locomotive. Gresley's own patent and drawings are close enough to what he was fitting anyway, or planning to fit, to his K3s and O2s prior to his meeting with Holcroft in 1919 that I have my doubts this can really be called helping on Holcroft's part.

Gresley went on to build over 1000 locomotives of varying sizes and wheelbase arrangements with conjugated valve gear, Holcroft produced...what, six total for the SECR? Who is helping who really here?

I have made an editorial decision for myself to not describe it in the book as "Gresley-Holcroft" valve gear. It is Gresley conjugated valve gear.

I am sure I will get criticism for this, but this is my opinion based on my observations. I feel we need to give Gresley more of the credit and actually recognise that it was far more independently developed outside of Holcroft than we have otherwise read.

 

True
The Henchel Wegmann was faster

 

A German train a third of the length of the LNER train, doing about a quarter of the mileage of the LNER train, is obviously going to have a faster average speed than the long distance intercity train doing a non stop run between the major cities of England. The achievements are not comparable.

The German train is impressive, for sure, but it is one locomotive and one four coach train. There were two sets for the Silver Jubilee, two for the Coronation, two for the West Riding and a spare set, and 34 A4 locomotives providing twice daily service for those trains for nearly five years. These trains were made up of between seven and nine vehicles with an observation coach added to the Coronation in the summer months and still maintaining the schedule.

The LNER achievement of a high speed train is the greater one I humbly suggest.