Air smoothed merchant navy

Sorry to drift of course slightly but this is the hottest Bulleid thread at the moment and as a result has some proper boffins casting a glance
Q: What was the thinking behind the extremely short piston stroke on MN'S/BB'D/WC,S ?

the coupling rods must 'shirley' be seated closer to the axle than on other Locos and perhaps this helps with hammer blow, but with the exagerated torque would make them more prone to slip....

Q Is there a modern equivalent to asbestos ? some of the Mn's had an experimental casing built of Asbestos Board...

Q Are any of the original boilers in a fit state to be taken to the original higher boiler pressure maximum ?

i Like the idea of a Geisl even though it wasnt a MN Feature,? Putting an angle into the foot of the smoke deflector slots would help to keep the exhaust clear of the sides but would alter the appearance only V slightly .
Extra tender capacity - with the 'Raves' fitted could be built into the tender with very little visible alteration, but structurally a bit of improvement on the original design would have to be made to cope with this...

It can happen, it should happen, lets make it happen....

 

Former Stewarts Lane shedmaster Dick Hardy was interviewed by Ron White for Bulleids in Retrospect and referred to 34090 as being one of the poorer locomotives. I believe crews sometimes referred to it as Sir USELESS Missenden (I may have mentioned this a few times before)!

I'm looking forward to seeing how this project develops. As soon as there's some progress towards a website that gives more details, I'll probably bung a few quid towards it. I suspect that because the boilers of the ex-Barry locomotives have not operated at the 280lb pressure for around half a century, there's no precedent for up-rating the 250lb pressure on an old boiler. If a new boiler was fabricated, the main benefit is that you know the tolerances of the materials used, whereas up-rating a restored boiler from a comfortable 250lb to 280lb after years exposed to atmosphere may just be the straw that breaks the camel's back when it comes to testing it.

'Limpet Board' (the asbestos sheeting) is an interesting one, as its a question of what similar material is safe to use and has the same qualities for withstanding the vagaries of weather. This makes me think that it will be a later batch of MN that will be un-rebuilt, as they didn't have the Limpet Board, so my money's on 35022. If there was a move to make a new boiler to 280lb, then this would be the ideal blank canvas, as its own boiler is being used to overhaul 35027.

As for the tender, one has to remember that there were wells either side of the coal bunker and behind the raves that provided (limited) rearward vision and storage for fire irons. If these are to be kept, then there is the issue of finding space for increased water capacity, which is usually at the expense of coal capacity. However, if it is a late batch MN (such as 35022), then ideally it would have the longer-wheelbased tender with a box-fabrication on the watertank roof providing extra water space, and the vacuum reservoirs placed on top of this. This is not un-prototypical, as several 'Light Pacifics' retained this when their tenders were cut-down (its quite difficult to explain without a diagram!).

I could be wrong about 35022, and the other candidates would probably be 35009, 35010 or 35011.

 

Just going back to 34090. Thinking about it overnight, weren't there some blast pipe changes made at some stage? That would explain it's different exhaust sound which I am certain it had.

 

I've mislaid my RCTS "Bulleid Bible" so can't quote chapter and verse but in 1951 Merchant 35019 was fitted with a single blastpipe. Tests showed that it wouldn't allow a steaming rate equal to that of a multiple jet blastpipe and AFAIK the experiment was discontinued. The only other blastpipe alteration I'm aware of was the fitting of the Giesel ejector to 34064.

 

i think that re-building a re-built MN should be a No1 priority AND that modern technology should be used to improve it so that the faults which brought about re-building in the first place are not present. Basically that would be improved lubrication system and reverser I imagine.I don't think thtre was much else wrong with them was there?

 

Apologies if this has already been mooted, but as a minimum surely a cosmetic retro-build/restoration could be done, so as to give a complete set of "streamliners" at the NRM? I don't buy the argument the the casing is an issue (plenty of WC/BB's have had it replaced). But what form should it take? I'd go for Bullied's original "widow's peak" - hey, get Scottish Widows to sponsor it! Of course, far better still would be a full mainline restoration - anyone mentioned it to the A1 boys?

 

What is the point in building what is supposed to be a replica of a loco only to change the design and modernise it? I can understand it for fitment of mandatory mainline systems if required like TPWS and OTMR. If you want an unrebuilt Merchant Navy you should be prepared to live with the faults. What you are suggesting with your mods is basically an alternative Rebuilt Merchant Navy not and Unrebuilt.

 

How long did the original MNs work with 280psi boiler pressure? I'd a feeling that they were derated to 250psi by the early '50s so ran for quite a few years in this form. If that's he case, why bother with the additional hassle of reverting to 280psi, which presumably was dropped for good reasons.

 

So, essentially, they should make it worse on purpose?

 

Sound point Corbs ! The A1 has several design improvements over the originals and look how she runs

 

So long as it will have the same basic components ie. chain-driven valve gear, Eastleigh steam reverser and air-smoothed casing, it shouldn't matter if there are any modifications made to make life easier for maintenance crews. It would still be an unrebuilt, just with a few tweaks here and there that would have been done in the 1950s if the technology was there. I always felt that the rebuilding programme was a bit drastic, despite Jarvis stating that they were still "90% Bulleid". As usual in this business, its always a personal question of where to draw the line in tolerating any changes.

 

And??

 

I dont understand what you mean in this context Stan.

 

Hope you don't mind, but I'm moving this last bit to the Bulleid thread so we don't take this thread too far off topic.

 

I guess that would be a decision for whoever actually goes ahead with this project, and those who fund it. News of whom we still have not had for posting here. Leaving this still as a very interesting debate, but not one that seems to point to anything tangible happening...........yet!

 

This might be interesting although it is drifting off topic.
http://www.nineelms.svsfilm.com/
Click on the locomotives link on the left, there is an article on 34064 & the Giesel Ejector.

 

what i mean by improve is (for example)to find a way to keep the oil bath oil-tight which would at a stroke reduce the cladding fires and slipping phenomena and reduce wear on the valve chain, therefore improving reverserer operation.Perhaps modification is too strong a description

 

what i mean by improve is (for example)to find a way to keep the oil bath oil-tight which would at a stroke reduce the cladding fires and slipping phenomena and reduce wear on the valve chain, therefore improving reverserer operation.Perhaps modification is too strong a description[/quote:8w5ldvlu]

Ah but there's good evidence to suggest the cladding fires - not exactly common - were not caused by oil leaking from the oil bath but overflowing from the trays in the cab. Oil then ran down the outside of the pipes, picked up by the wheel treads and then flung up onto the lagging.

 

here's something to think about. what components do bulleid pacifics and S100 USA tanks have in common? its not firth-brown wheels....

 

Cab valve handles maybe - neither use brass as far as I can recall?