Bulleid Pacifics - Past or Present

That does kind of prove the point that was being made. 31 out of 80 (I haven't counted but I'll take your word) engines are Bulleid pacifics! That's almost 50%. There isn't much else in the way of express passenger engines either in that list compared to what's left from the GW and LMS survivors.

 

I think that proves the point I was making, 1/4 of all the Southern locos are Bulleid pacifics. Of the others, (and there is a bit more variety than I thought) many are sole survivors, so if you want a Southern engine and you're not wanting a small tank and you're not the Bluebell....you get a Bulleid pacific. All I was saying really was that by the time preservation really got going, the choice of southern engines available was more limited than other regions. Maybe that's just my impression though.

 

How many ex LNER locos were preserved from scrapyards?

 

Noooo - even more complexity!

Make that outside Walschaerts and a Holcroft/Gresley 2:1 and you can still have the inside big end in an oil bath if you really want to.

 

Not going to look very original then ?
More like a rebuilt with the spam can refitted

 

Please explain your experience with maintaining normal Bulleid Pacific locomotives.

 

It has to be said that many of the failings of the original Bulleid design were also down to the quality of the materials used. I'm one of the armchair parade that believes that based purely upon written and oral evidence, Bulleid was simply ahead of his time as regards some of his ideas, and that contemporary technology was pushed to the limit, if not beyond. Nowadays, we don't really hear about lagging fires (have any occurred in preservation?), leaking oilbaths and steam reversers that seem to develop a life of their own, and a lot of this is probably down to improvements in the quality of the materials used, and advances in how the technology needed to produce complex fabrications (ie. welding) is used. The only major problems I've heard of late as regards Bulleids are firebox cracks (34059) and broken combination levers (34070).

 

I suspect that the unrebuilt locos that have been put back on the road are actually maintained better than BR used to. They certainly don't do the mileage the BR locos did, or the speeds (even the main line certified locos). I'm not sure "ahead of his time" is the right phrase more "brilliant but misguided". Bulleid was very clever, but he seems to have been trying to apply IC engine principles to EC engines. Totally enclosed oil baths and spray lubrication for cranks and chain valve gears and the use of sleeve valves on his Leader locos all seem to be rooted in IC engine technology. I would have thought the better route for improvement of steam technology on the railways would have been to follow the heavy marine steam engine route from reciprocating engines to turbines. I wonder how well Bulleid might have done with that.

Enough.

 

We'll have to agree to disagree there. Ergonomically-designed cabs (apart from the lubricator on 21C1 and the poorly-sited brake valve obstructing the view)? Steam-powered electrical generators fitted to the locomoitve? UV-lit gauges? Lights to light the rear coupling? No-one else came close to such innovations, although I agree that they became a fitter's nightmare (although ironically, if they knew then what we know now in terms of the materials used, they might actually have been the fitter's dream locomotives). Welding technology was in its infancy when Bulleid used it, and he was certainly one of the pioneers of using welding on the railway. I get the feeling that Bulleid saw that the steam engine was on the decline when he took over on the Southern (a bit of a no-brainer, as it had already achieved the most comprehensive suburban electric railway network in the world), even though 4468 had yet to achieve its record. The war merely compounded the situation, and I believe that the MN/BB/WCs were his attempt to get his ideas 'out there' before it was too late, despite the risks associated with rushed introduction and the inability to refine his ideas in the cool of the evening. The use of chain-driven valve gear wasn't even his first choice, but wartime expediency left him little choice if he was to see his vision in metal. The path he trod between EC and IE engine priciples merly hinted that there was another way; combining the potential benefit of trouble-free 'sewing machine' running with a home-grown fuel source. It was just a shame that materials and mantenance regimes were not as stringent as they are now. If they were, then maybe the Crewkerne incident with 35020 might not have happened? A lot of what-ifs and personal interpretations, but an interesting discussion, all the same.

 

Certainly those sorts of innovations were worthwhile, but they were methods/details of construction and use, whereas I'm more concerned with the maintenance difficulties. I would add a good steaming boiler to the list of positives.

Quite possibly- even probably- but that doesn't mean his ideas were right, just different. I'm not sure how he could have refined them to make them significantly easier to work on.

Interesting, I'll have to see if I can find out what he originally had in mind.

The LMS had already shown turbines could provide that quite well, until I believe the war stopped spares being delivered.

True, though I don't think they were not the only class to have mass withdrawal for design/material faults. That's one problem I wouldn't place at the door of OVSB

 

Reading Winkworths book on the Bulleids. It points towards Bulleid going for poppet/ rotary valve gear. But the qualit of the metals around at that time prevented this actually happening and also WW2.

 

Wasn't there also an issue that available capacity to produce the ball / roller bearings that he planned to use in the valve gear were all earmarked for the aero engine industry, so he had to go to chain drive which worked better with plain bearings? Or did I imagine that?

Tom

 

The thing is, I don't think he believed that there would be maintenance difficulties when seen on paper, as the majority of components that could fail were nicely sealed away inside the oil bath, away from contamination and damage from most external influences. Oil-changing aside, it was probably envisaged that it would not need re-opening or any tinkering-about until the next major overhaul. Ironically, it is possible to argue that he was trying to 'ease maintenance' by designing-out the need to regularly oil around inaccessible areas between the frames, and thus reducing the reliance on manpower to some extent; a necessity in wartime. However, I agree that that the theory didn't quite work out that way in practice (particularly if you needed to access the middle cylinder for anything), but many of the issues that arose once the types were out on the road brings me back to my point about the materials and limitations of the technology available at the time...

Many of the problems associated with the choice of valve gear (leaking oil bath and by extension the ability to self-combust; combination lever failure, 'chain stretch' and the steam reverser's propensity to do whatever it damn-well liked) can be laid squarely at the door of the quality of the materials used and the technology available to ensure consistency of manufacture. Over the last four decades, we seem to have developed the methods and practices that the unrebuilt Bulleid pacifics have always needed to operate reliably, hence why I say that Bulleid was ahead of his time. That's my take on the subject, anyway.

 

Seems to me that one of the problems of an enclosed oil bath for the inside motion is that it also encloses the piston and valve glands and if they leak the outcome is an emulsified mush in the oil bath and replacing umpteen gallons of oil ruined in this way is always going to be an expensive option compared to the amount of oil applied conventionally. I think this is a problem that would never go away, even the bet gland packings seem to be susceptible to slight leakage.

 

The piston and valve glands are not within the oil bath.
http://bulleidsociety.org/21C123/Pictures/Valve_Gear/valve_gear_dia.gif

 

It all looks quite simple in that diagram, much better than the picture in the black book.

To sum up the arguments about Bulleid locos: Marmite.

So nobody is right - except those who like Bulleids and Marmite - obviously.

 

Just finished eating a Marmite sandwich as it happens.

 

Originally Posted by 61624
Seems to me that one of the problems of an enclosed oil bath for the inside motion is that it also encloses the piston and valve glands and if they leak the outcome is an emulsified mush in the oil bath and replacing umpteen gallons of oil ruined in this way is always going to be an expensive option compared to the amount of oil applied conventionally. I think this is a problem that would never go away, even the bet gland packings seem to be susceptible to slight leakage.
The piston and valve glands are not within the oil bath.
http://bulleidsociety.org/21C123/Pic...e_gear_dia.gif

Sorry, my mistake.

 

No worries. Pleased to have added to your enlightenment.

 

The Sentinel engines also have separate glands on the piston rod for the steam side and the crankcase. It doesn't stop their crankcases from filling with water and draining them is part of the daily preparation.