WCME & CME 2025

Maybe it would if it was running solo

 

Hi Al
I think this is a commonly held myth - in fact 34092 acquired the nickname “The Volcano” before the Giesl ejector was fitted in 1986, some way into its 1981-1988 period of main line operation. If anything, the Giesl elector may have mitigated the exhaust position slightly with the crisper blast.
Best wishes
Julian

 

My recollection from standing at Dulwich cricket ground all those years ago is that the 73A common user locos which included 34066-70 were all prone to filthy exhaust when working hard going up the 1 in 100, whereas the two Brits and the Arthurs were comparatively clean.

 

Just a hunch: Most of the coal in circulation at the moment is high in volatiles, which causes smoke. Normally you would control that by adjusting the firehole doors to get the right amount of secondary air.

On a Bulleid, the design of the doors means you don’t have much control - basically you have “shut”, “wide open” and only I think two other positions in between. So it is hard to adjust the doors to a position that is “just right”; the likelihood is that you have too much secondary air (which cools the firebox and reduces steaming) or too little (which causes smoke). In the circumstances I suspect most firemen would err on too little, with the resulting smoke. The adjustment is not helped by virtue of the fact that the doors are also heavy to move, which discourages trying to find a good adjustment.

By contrast, on a Britannia with sliding doors, essentially you have infinite control of the secondary air so it is easier to find the spot where you just get a haze at the chimney, even with coal with a lot of volatiles.

Tom

 

How difficult would it be to add some sort of baffle plate to give finer adjustment?

 

Well, they already have a baffle plate anyway.

Probably best seen by inspection. There's a panoramic photo here that you can move around to show the general arrangement of the doors. They are moved by the long lever heading diagonally off to the right, but only have five positions between shut and open. http://www.mikeanton.com/360panos/Bluebellrailway/blackmoorvale2007/blackmoorvale2007.html

Even clearer is to watch this video, particularly the first few minutes, which shows the doors being used. Round about 2m30s onwards you can see the fireman adjust them to control the smoke.



Ultimately, to get finer control would take a complete redesign to a different type of door; it isn't something you can easily tweak. As designed, those doors do have holes in them to allow a small amount of secondary air, which is probably all you need with low volatile coal.

Tom

 

I don't like those butterfly doors, if someone tries to pull themselves out of the firebox by grabbing hold of the handle they'll know all about it! The Midland/LMS firedoors are much better with no ratchet. Does any Bullied in traffic now still retain the steam worked firedoors? I remember Bert Hooker telling us he wouldn't let his fireman use it having witnessed one getting his hand trapped in the doors.

 

You could of course restore the steam operated door mechanism as Ajax (the American esigners of these doors) intended. In America they were air operated by depressing a foot treadle but the steam operation is just as effective provided it is maintained properly. One of the reasons that they were so heavy is that they were intended for power and not manual operation.

Peter

 

I seem to recall that when City of Wells visited date Bluebell some years ago, it had working steam-operated doors.

I went on a JA 4-8-2 in NZ and it had them as well, also worked by compressed air. But even so, you still don't get fine control of top air, I don't think.

Tom