Big Bertha- a few questions

Automatic blowdown?

Regards

 

It's probably the Continuous Blowdown, applied to many engines, for keeping the boiler water comparatively clean, which was originally routed through the tender to disharge on to the track. The Chief Civil Engineer began complaining of corrosion to the rails and chairs, so it was redirected into the locomotive's ashpan.

 

Well I never knew the blowdown used to be routed there - why would you want to do that? It would require another flexible connection between loco and tender for a start.

 

Maybe so the water which turns into steam once it has left the pressure of the boiler has a chance to condense into water again, or maybe because a continuous jet of high pressure steam exiting just under the cab would be really annoying.

Tim

 

Well thought out. They might have even run it through the tank to ensure it condensed, unless it would have heated the water significantly.

 

Thanks for the correction, the phrase is 'continous blowdown'. And you are right too that the 'Chief Civil Engineer began complaining of corrosion to the rails and chairs, so it was redirected into the locomotive's ashpan'.

In reply to 'Sheff' the water jet would contain deposits from the boiler (the entire idea was to get rid of these) so it wouldn't be good idea to condense the water stream in the tank (because if you did, you'd then be transferring the boiler deposits from the boiler to the water tank).

Regards

 

Actually, Orion, it wasn't s correction: your post must have landed a few milliseconds before mine so I hadn't seen it! I would have accepted 'automatic' anyway.

From memory, the waste pipe did travel through the tank to condense the water, but did not discharge into it for the reasons stated. I have to say that it does look more like steam in the photo, though.

 

There's a photo in the current Friends of the NRM magazine of Big Bertha being scrapped at Derby

 

I did say through the tank, not into it, so it would be condensed indirectly. You would still risk heating the water. But the blowdown flow is pretty small so temperature rise may not be significant depending on the water level.

 

Deleted double post

 

Brilliant! Is it yours Selsig? What gauge is it? What drawings were used?

 

Not mine - it was a visitor at the Echills Wood Railway (7 1/4" gauge) Standard Gauge Weekend, earlier this year. I only drooled at it out of the signalbox window, and never got the opportunity to ask the owner where it was based, or come to that, who he was. Sorry.

John

 

Think it was more than the tender off the Paget experiment? Smokebox & chimney supposed to have been used? Don't think the frame was the same as I havent looked at drawings yet.

 

The headlight was indeed saved.

In the early 1970s Columbia Pictures (Richard Attenborough) borrowed it to fit to David Shephard's 9F 92203 "Black Prince" as part of its disguise as a South African engine in the film "Young Winston" that was filmed partly on the Longmoor Military Railway at Liss (Hampshire). Photographs of the headlight appear in David Shephard's book "A Brush With Steam".

I knew an ex Bromsgrove fireman called Ron Walker, who untill his death in 2000 was a volunteer fireman on the Welshpool & Llanfair Light Railway (unsuprisingly he enjoyed firing up the W&L's 1 in 29 Golfa Bank!). Despite several requests, he refused to train as a driver as he always prefered to fire and to teach trainees how to do it. Despite the size of the narrow gauge fireboxes he always insisted on huge wedge-shaped fires. He was often persuaded to talk about the 0-10-0. The "Big Bertha" nickname came from railway enthusiasts, probably due to the large German gun, but most of the older railwaymen actually called her "Big Emma" (on account that her bufferbeam was marked "MR" in pre-grouping days) but it gradually changed to "Bertha" in later years. I often think of Ron when I enjoy a pint in the Brunswick (opposite Derby Station) where one of the snugs used to be decorated with photographs of the decapod.

Gareth

 

Is this it?



from East Somerset Railway website

Richard

 

Thereby proving what a handsome loco the 9F is sans smoke deflectors...like an elongated 5MT...

 

My favourite "Ron" memory is of him returning to Llanfair on Countess, sweating as he had emptied the coal bunker, and complaining that the "cowing engine won't steam today". Turned out the grate had collapsed not long after leaving Welshpool, but Ron had gamely baled in the coal up to the the level of the doors from the ashpan! How it didn't warp the ashpan I don't know, but all that was left of the fire bars was a spiky lump of metal about the size of a football!! Fair play, he got the train home though!

 

I'm curious was the centre driving wheel flangeless as per the 9F's? Some pictures appear to suggest it was but it would be hard to know without seeing a more detailed one.

I did have an image of it being scrapped which I think was in a Hornby book on the London Midland Region which I don't have access to at the moment!

 

A quick Gurgle (other search engines are available) suggests that they were indeed flangeless.

In similar vein, it looks as though the GER Decapod was also fitted with flangeless centre drivers

The Austerity 2-10-0 middle drivers are flangeless too - there seems to be a pattern developing here

Mark

 

Yes, I've heard that before and believe it to be true. Online accounts suggest the idea was copied from the Italians who had some compound 0-10-0s with crossover steam ports. You're right in thinking that the middle cylinders had no valve gear of their own, only the bits associated with the drive from the cylinders themselves (pistons, slide bars, crossheads, con rods, big ends).

I'd imagine crossover ports are probably best suited to machines that will operate at relatively low piston speeds. They'd also need considerable care at the design stage to avoid choking the front end - don't forget this was long before the concept of "internal streamlining" had taken root. Given that MR blocks had torturous steam passages at the best of times one has to hope that Italian practice prevailed and it wasn't "Midlandised" too much!!!