L1 new build

I am nothing to do with the L1 group. If you took your time to read up on the L1 locomotive class you would be aware that 10 Neasden based locos were modified with manganese steel liners to the driving horns and axleboxes in 1954. This modification eliminated many of the problems experienced with the frames and motion on the locos. Other members of the Class were not modified because of the onset of the 1955 BR Modernisation Plan. No doubt, the NRM will have the relevent drawings in their Doncster Works archive.

 

I am fully aware of this, it just seems a pity that the groups spokesman isn't! If he could have given the answer you did I would have been rather more reassured that some one at the project knows what they are talking about.

 

Bullied can never have consulted anyone having practical experience of sleeve valve internal combustion engines. They were very expensive to make on account of the precision needed and, as a consequence, were largely confined to luxury cars and aeroplanes.

My grandfather ran a garage with many customers in the "carriage trade". He told me that if the chauffeur of a sleeve valve Daimler (they were almost always chauffeur driven) put his foot down when the engine was cold on a February morning, it was asking to break a sleeve driving lug. Minervas and Panhards were better but all had a gigantic thirst for oil. With Rolls-Royce and Hispano as a comparison, he saw no point in sleeve valves and, indeed, they had mostly disappeared from the private car market by W.W.2.

As far as aero engines are concerned, I have heard exactly the same from the son of an R.A.F. fitter who maintained Napier sleeve valve engines in Typhoons and from a Fleet Air Arm officer responsible for operating Bristol Centaurus power units. None of these people ever met one another.

So if power units operating in relatively clean conditions in the hands of professionals needed very careful handling, what on earth was Bulleid doing transferring the idea to the rough and ready conditions of steam locomotives housed in grimy (at best) running sheds? It all seems a touch half baked.

 

Many years ago I lent a book on Bulleid and the Leader to a (much older) friend who was a qualified Mechanical engineer who worked in the motor industry.

He returned the book to me saying he had sympathy with some of what Bulleid was striving to achieve with his steam locomotives until he came across the idea of sleeve valves. at that point the friend said " as we were never able to make the things work reliably in car and aero. engines how on earth did he think they were going to work on a steam loco?" he concluded by saying " he had obviously cracked ".

 

At the risk of being the subject of a "contract" from the Bullied mafia, let me cite another instance of OVSB pecking at an idea from somewhere else which did not translate particularly well. This is the power operated "butterfly" firedoor.

Devised in the U.S.A. this seemingly worked very well when powered, as the designers intended, by compressed air. Operated by steam, as it had to be in the U.K., it proved troublesome.

A pattern begins to emerge.

 

And of course the fact that given the choice between the Ashford steam-powered reverser (which worked very well) or the Eastleigh one (which was troublesome), he chose the Eastleigh one, with the consequence of the well-known problems of setting cut-off on a Bulleid pacific. This is often ascribed to the revolutionary valve gear, but I believe it actually had much more to do with choosing the wrong reverser, especially when an entirely satisfactory one was available (in particular, the fact that once set, the cut-off tended to drift).


Tom

 

Another point is sleeve valves were more "happy" in constant speed engines, possiably why they found most favour in aero engine. You cannot think of a more variable speed engine than leader's power bogies!

 

The biggest problem, as I understand it, which was realised very early on by the Midland's people after being confronted by Paget's locomotive, was different expansion rates within the engine, which led to seizing of the valves. The clearances of sleeve valves are, by necessity, tight. I suspect that OVB thought that improved materials and lubrication which were available to him some 30 years after Paget's efforts would overcome this. He was wrong...

 

All this points to a personality who needed to be subordinate to a Gresley figure who could say "What justifies this suggestion? Have you thought it through sufficiently? No we will not be doing this" Without such a figure there was trouble.

 

There is an implication running in this thread that sleeve valve engines were unsatisfactory in applications other than railway locomotives. As is the case for all engines, a design is the result of a series of compromises and sleeve valves have advantages and disadvantages compared to other valve mechanisms. However, the series of sleeve valved aircraft engines developed by Roy Fedden at Bristol, were highly successful and the Hercules and Centaurus were important contributions to eventual success in the air war from 1939 - 45. More than 1/4 of WW2 RAF aircraft were sleeve valved. They were operated reliably in far from ideal conditions ranging from the desert to the arctic. Fedden is one of the forgotten heroes of British engineering.

 

It was the Bristol Centaurus engine which the erstwhile Engineer Commander I mentioned in my previous post was referring to. In the circumstances of a disciplined service the sleeve valve principle could be made to work but this required, inter alia, very careful warming up before take off. Rolls-Royce, or Daimler Benz for that matter, avoided sleeve valves to their evident advantage.

In the possibly less formalised world of the high end private car, where the temptation to floor the accelerator before the motor was warmed through was not always resisted, the result was plenty of work for garages such as that run by my grandfather!

To my mind Bullied can be criticized on two counts. Firstly, instead of pecking at an idea, he should have spent a little time in asking Daimlers as to why they had given up sleeve valves in the nineteen thirties. They might have told him about the precision engineering needed to give this system even half a chance. A few discreet words amongst the motor trade would have helped. Secondly, how could he have been so ignorant of the conditions of the average running shed?

 

I may be wrong, but I think you are. Bulleid was adamant that the Ashford (James Stirling) design be used - but Eastleigh simply refused to build it for him, they insisted it was their way or the highway. I think Bulleid outlined this in a book he wrote in retirement. However, I do not have a copy thereof and have only read snippets of it online. What Brighton, with no history of steam reversers of any kind, did with the Light Pacifics, I have no idea. Weren't the last ten Lights built at Eastleigh? In that case I'd presume those examples used the Drummond type (I dare say the chaps working on 34105 can confirm this), but what of those on 34007, 34023, 34051, 34067, 34070, 34072, 34073 (or what's left of it!), 34081 and 34092? Are they all the Drummond type too? Oddly, nobody ever seems to moan about the Drummond reverser in conjunction with the M7, or the T9.

Certainly - especially given Maunsell's relative conservatism in later life compared to his contemporaries - Bulleid's Pacifics were extremely audacious and adventurous in innovation, perhaps too much so considering he was working in the wartime/immediately postwar material-rationing era, with some of the materials and components he wanted simply unavailable (I've an idea he originally wanted some kind of shaft-driven oil-bath valve gear, but had to settle for chains, which had a bit of a habit of stretching and jumping) - yet, there's nothing quite like them for steaming like buggery and free-running qualities... and the way they were able to displace vastly smaller, less powerful antiquated locos on the lines of both East Kent and North Cornwall... the rebuilds arguably went too far, making regressive changes (not least the reintroduction of hammerblow and making them too heavy to go to Halwill and points west, and also I think to go to Ilfracombe).

 

It would be interesting to know more about the Holcroft-Bulleid relationship. Holcroft is very measured in his book, but its hard to avoid the suspicion that Bulleid wasn't very interested in other people's ideas. Is it revealing that Holcroft doesn't mention the Pacifics at all in his book Locomotive Adventure even though he was Bulleid's Technical assistant at the time they were being designed?

Brighton Baltic, that's a remarkable story about Eastleigh refusing to build what the CME wanted. Could they really get away with that in those days? Presumably you mean that the Eastleigh drawing office refused to design it or said they couldn't make it fit rather than the works refused to build what had been designed?

 

No doubt there we're ways and means, like getting friends in the P'Way dept to reject the design....

 

Jimc, knowing what I do of industrial politics even far more recently than that, yes, I do believe it entirely possible that the Eastleigh guys would have gone on strike had there been an attempt to make them build Stirling reversers.

 

I can't find any reference to Bulleid being so adamant about the design of reverser - certainly it isn't mentioned in any of DW Winkworth, HAV Bulleid or DC Bradley's respective books. I suspect Bulleid would have preferred a screw reverser, but it couldn't be designed to fit around the firebox and hoppers, hence the steam reverser. The closest any of those sources come to in respect of which design was chosen is in HAV Bulleid's book, which simply notes that the Eastleigh drawing office adopted the Eastleigh design - I suspect they simply fitted in what they were already familiar with, which isn't that surprising. Given the large number of other radical innovations in the design, Bulleid probably had bigger issues on his mind that worrying about a relatively minor, off-the-shelf component, even though in retrospect that component became something of an achilles heal of the design.

I seem to recall a conversation with an engineer familiar with both forms of reverser that although the Stirling reverser provides a more accurate and consistent setting, it is also more complicated to manufacture, which may well have been an overriding factor during wartime.

Unlikely - I suspect there is very little weight difference between the two, certainly not in the context of a 135 ton locomotive.

I find it unlikely that the drawing office was openly obstructive; more likely just somewhat conservative in looking outside Eastleigh for solutions. OS Nock quotes a conversation between James Clayton and T.S. Finlayson, the LSWR's chief draughtsman. When Clayton tackled Finlayson about why a King Arthur weighed 81 tons for a nominal TE of 25,300lbs, while a GWR Castle weighed one ton less for a nominal TE of 31,600lbs, Finlayson is reputed to have been drawn no further than to remark that he supposed "the spec-eefic gr-r-avity of the steel was differ-r-rent at Swindon"!

Tom

 

Maybe, but if you're tight for space and weight, and who isn't on a locomotive built right up to the limits of the gauge, maybe its human nature to be unable to find space for the device that you don't like, and be readily able to find space for the one you do... The org chart in Locomotive adventure vol1 1 suggests that Waterloo produced the concept, but Eastleigh was responsible for the detail design (what an odd way to work, although goodness knows its not unique). But as I've said to umpteen executives 'its the detail where you fail'. All the basic concepts round the original (unrebuilt) pacifics were reasonable enough things to have a go at, but the detail engineering let it down in so many ways. Not to blame the Eastleigh staff for that, wouldn't be the first time a grand concept fails because the technology and materials aren't ready for it.

 

I think there was quite a lot of "human nature" at Eastleigh, as revealed in Holcroft

I was trying to find a good picture that showed how the reverser was packaged between the frames on a Bulleid pacific, but can't easily find one, though this photo shows the reverser removed from the loco: https://picasaweb.google.com/116839141471298057728/26Restoration2013#5948795116939601266

I've not measured, but if I had to take a guess, my feeling is that the Eastleigh reverser is actually bigger than the Ashford one ...

Tom

 

I never understand why the Southern & its constituent companies were using power reversers when the rest of the Big 4 got on perfectly well with manual.

More to the point however the SAR Class 26, AFAIK the worlds most efficient steam loco basically worked as well as it did as a result of proper understanding of how the steam loco worked and attention to detail.

On its own none of its features were remarkable unlike the spam cans

 

Without knowing anything about the power reverser issue in Bulleid's time, there is ample evidence in biographies and reminiscences that relations between Head Office and Eastleigh were very difficult and that Eastleigh tended to do their own thing unless sat on very heavily.

Bullied dropped the sleeve valves and other complications for the Turf Burner, so he did at least learn from experience.

I don't understand why most UK railways never used power reverser - several satisfactory ones had been produced, not least the Ashford one which dated back to the G&SWR in the Victorian age, due to James Stirling working for both railways. Not Invented Here writ large, I'd suggest.