Edward Thompson: Wartime C.M.E. Discussion

That is not, as I understand it, strictly speaking true.

There was absolutely nothing wrong with the water tube boiler when used on the W1; it was everything else such as the auxiliaries, injectors and numerous other details which needed tweaking - including the fitting of the double kylchap exhaust which was fitted late on in the locomotive's life.

Whilst there are several points I disagree with in William Brown's book, the overall point when looked at the W1 experiment in context is that it was actually very successful at producing a locomotive equal to a Gresley A1 but (in theory) more fuel efficient.

I think to say the water tube boiler didn't work well is too simplistic a way of looking at the overall story of the locomotive and its development, if I may say so.

Particularly when one considers that the only component not modified throughout its lifetime was the water tube boiler itself, fitted as a stationary boiler thereafter and in theory gave 30 years continuous use with little renewal of parts compared to a standard locomotive boiler.

The W1 could have been re-boilered with a Peppercorn boiler (as per the Thompson Pacifics) but the reality of its withdrawal was that it was a class of one - and as per the Thompson Pacific classes and several other small classes (class V4 for instance) the smallest classes where withdrawn first, any expenditure to be spent on keeping the largest classes running.

More's the pity as it robbed railway preservation of the most powerful express passenger locomotive in the British Isles.

 

Problems with keeping the water tubes water/steam tight were well documented. Such a boiler was far better suited to marine/stationary use where it avoided the rough and tumble of the railway environment.

 

Where is this well documented? I can't find mention of that specifically in my books. I can see from Brown's and Cecil J. Allen's books that the "boiler walls" (not the same as the water tubes) had difficulties due to the fluctuations of the temperature between the plates. Arguably this issue was about air being drawn through gaps between the plates instead of through the grate, and this was a potential cause of poor steaming too.

Can't argue with that - the boiler itself proved that as a stationary one. However I don't think necessarily the boiler itself was the problem - it was able to produce steam satisfactorily but everything else seemed to fail when the locomotive was on the move.

The injector issue is one which baffles; then when fitting the double kylchap, they were able to bring the temperature in the smokebox down, but this created condensation in the LP cylinders. That then required the fitting of a superheater…the problems seem to be exacerbated by the whole thing rather than one specific problem.

 

Were there any successful railway applications of water tube or other "non-conventional" boilers? In most examples I can think of, the theoretical thermodynamic gains of running high pressure / high temperature systems were outweighed by additional maintenance costs - which seems to be the issue with the W1. So did anyone (in any country) successfully apply a non-firetube boiler to a railway locomotive?

Tom

 

http://www.aqpl43.dsl.pipex.com/MUSEUM/LOCOLOCO/USAhp/USAhp.htm shows several American locos, though none seem to have been especailly succesful. It is notable that the two boiler photos show pretty much a watertube firebox and normal boiler barrel, whilst the W1 had mostly water tubes with collector drums.

 

Great link Lplus !

 

Fascinating pictures and locomotive. The similarity in the firebox arrangement to no.10000 but difference in the conventional boiler tubes is very interesting. Worthy of a thread in itself.

 

I wasn't referring to W1 as built, I was referring to the one that BR inherited, which spent the 50's doing nothing in particular. Or rather, nothing that an ordinary A3 (or even V2) couldn't have done.

The P2's would have been withdrawn as early or earlier had they not been rebuilt. Small class, over-powerful for the work available and hence inefficient.

The original W1 was an entirely worthwhile experiment that just fell short.

 

The problem if you have a one-off is that it has to fit into diagrams that can met by more common motive power. So if you have a rare locomotive more powerful than the norm, it will generally not be able to be rostered to use the full power, because you can't guarantee its availability. (The same happened on the SR with the Lord Nelsons, which - although more powerful than a King Arthur - were generally rostered on diagrams that were within the haulage capacity of a KA because there weren't sufficient Lord Nelsons to guarantee one would always be available).

Tom

 

Sorry, Tom, was editing while you were replying.

No-one was ever going to build more P2's or W1's, not even Gresley had he lived, so they simply would not have lasted longer than 1959-60 regardless whether rebuilt or not. By that time average train weights on the ECML had typically shrunk by about a third (linked with a speeded up more frequent service) , and even the A1's were a bit over engineered for the job, hence the glorious Indian summer of the A3's.

Had the P2's stayed in Scotland they'd have been withdrawn even earlier as the post war service didn't need anything more powerful than a V2.

 

The W1 features rather prominently in Edward Thompson's comparison runs; he seems to have a rather positive view of the locomotive when rebuilt and was involved with the locomotive (albeit in a minor capacity) during its development.

 

Somebody asked about widespread use of water tubes. On the same site as linked earlier, there's this. Not full water-tube boilers, but ~1000 locos built with water tube fireboxes in Hungary, due to a lack of indigenous copper reserves. Baldwin No. 60000 used a pretty similar arrangement. As far as I can tell, these weren't used to allow for increased boiler pressure (although ditching flat stayed surfaces is obviously a great advantage), just because of distrust of conventional steel fireboxes. Greater efficiency seems to have been claimed, but the steam was wetter, good water treatment was absolutely essential (some might argue it should be with any boiler), and our old friends of poor tube-drum sealing and vibration-induced fatigue seem to have been an issue.

The link comments that although several locos with these boilers are preserved, none are active because the tooling and expertise for dealing with these fireboxes is no longer available in Hungary.

 

That is not, as I understand it, strictly speaking true.

There was absolutely nothing wrong with the water tube boiler when used on the W1; it was everything else such as the auxiliaries, injectors and numerous other details which needed tweaking - including the fitting of the double kylchap exhaust which was fitted late on in the locomotive's life.

Whilst there are several points I disagree with in William Brown's book, the overall point when looked at the W1 experiment in context is that it was actually very successful at producing a locomotive equal to a Gresley A1 but (in theory) more fuel efficient.

I think to say the water tube boiler didn't work well is too simplistic a way of looking at the overall story of the locomotive and its development, if I may say so.

Particularly when one considers that the only component not modified throughout its lifetime was the water tube boiler itself, fitted as a stationary boiler thereafter and in theory gave 30 years continuous use with little renewal of parts compared to a standard locomotive boiler.

The problem I have is that you seem to be making sweeping statements and drawing conclusions based on what is, at best, secondary evidence, unless you have access to the maintenance records for the boiler - which I would expect to exist, at least for whilst it was installed in the loco.

 

William Brown's book gives an extremely detailed account of every modification made to the locomotive throughout its service life in its original condition, in addition to many fascinating photographs and snippets from letters between Gresley, Bulleid (on occasion Thompson) and other interested parties and engineers.

That includes all work on the boiler (including drawings and photographs) and I cannot at this time find a reference to the tubes themselves leaking but plenty regarding the boiler plating and the grate.

So no, I'm not working from secondary evidence at all - I am drawing my own conclusions based on first hand accounts, details and photographic evidence (including some very insightful pictures of the boiler with the outer cladding removed). I think it's clear from Gresley's own words that the intention was not to produce a locomotive better than an A1 but comparable to it in terms of performance but bettering it in terms of fuel efficiency.

That the W1 was always playing catch up to the A3 and A4 classes is neither here nor there - if you look at the whole picture, it was successful on a number of levels and the theory was proved somewhat by some of Chapelon's work after the W1 had ceased to be and Gresley had passed away.

I would highly recommend William Brown's book if you enjoy looking at the minutiae of developing an experimental locomotive. The full title is Hush-Hush: The story of LNER 10000. You won't necessarily agree with everything in the book but it's fair to say that the content is top notch and by far more detailed and thoroughly researched than many books on other locomotive classes.

 

Not modified is not quite the same as being low on maintenance. Interestingly, one Hungarian solution to vibration related failures of the tube-drum joints appears to have been a conventional stayed firebox front and rear to improve the rigidity of the connection between foundation ring and barrel/top drum, at which point one might wonder exactly what the advantage of having water tubes is at all (apart from eliminating those pesky crown stays).

 

Dugald Drummond was rather partial to firebox cross water tubes on his engines, (which otherwise had conventional boilers) supposedly to help improve water circulation rather than as a means of improving absolute thermodynamic efficiency. Drummond swore by them, but when Urie - ever the practical workshop manager amongst CMEs - took over, he had them removed pretty much as quick as the engines went through the shops!

(You can recognise Drummond locos with cross water tubes as they have a large raised oblong cover on either side of the firebox. See photos 131 to 133 on this page: http://1920slocomotives.blogspot.co.uk/2014/03/111-140-early-locomotives-and-in-works.html).

Drummond did also experiment with a true water tube boiler - see 137 and 138 on the same page.

Tom

 

I don't disagree with that at all: but the maintenance problems reported and I've read on all seem to be related to bits bolted onto the boiler rather than the main cause of the W1s problems being the boiler itself.

There's a lot of work that needed to be done to the auxiliaries for example, and the manifold for those in addition to the injectors.

I'm not disputing that the W1 as a locomotive required lots of maintenance: I just think pointing the finger at the water tube boiler and its application is a bit simplistic based on the evidence in front of me. That's all.

That is interesting - is that on the link above?

Perhaps the water tube boiler debate deserves its own thread, I'm finding it to be a fascinating topic.

 

With the partial exception of the M7, I don't think there was a Drummond class that wasn't improved by Urie simplifying and superheating. I even think most of them looked better post-modification too, a T9 or 700 just wouldn't be the same without that smokebox overhang. Maybe the cross-tubes did aid circulation, but they must have been a right pain to work with, especially those big access covers.

Yes, the bit about the stayed front and rear firebox walls was from my previous link. Very interesting page, although it takes a bit of digesting.

My view is that with a conventional water tube boiler (and the basic Brotan-Defner boiler), you get comparatively heavy objects (the top drum and the bottom drums, or the top drum and foundation ring) that are linked only by the tubes. To allow for expansion, you've got to pick one or the other to attach to the frames, probably the bottom drums (that seems to have been naval practice). So as the loco bounces and vibrates along, all the load from the top drum is having to be carried through the tube/drum joints at each end, and it's no wonder they start to work and leak. With the stayed walls front and rear in the Brotan-Fialovits arrangement, the foundation ring and top drum are tied together in a pretty solid structure, so the tubes joints only have to deal with thermal and pressure loads, which have a much lower frequency and are less of an issue for fatigue (but you've got stayed flat surfaces again, so the scope for high pressure is much reduced).

 

If you're going to quote from someone else's book which includes their use of a primary source than you are quoting from secondary sources which doesn't give you as much credence as if you quoted from the original primary source and its archive. I read a book recently that only referenced secondary sources for about 90% of its material and I felt that the author hadn't really done any original research (it was still an interesting book).