Last weekend we spent an entertaining day out at the Manchester museum of science and industry. (I'd post a link, but their site seems to be down right now). I loved the aircraft section, and fell head over heels in love with the Shackleton they have in there (I want one, but my garage is cluttered enough already, and I don't think I could hide it from Mrs WTM anyhow) but steam engines always grab my attention too. There was a static triple expansion engine there, and it always struck me as a piece of sheer genius to come up with it in the first place. Very widely used indeed in ships, but does anyone know why they never seemed to be used in locomotives?
I've asked a couple of people who claim to be railway enthusiasts (I know a bit, but not a lot) but no one seems to be able to give a conclusive answer.
By far the biggest item in the steam hall is a steam locomotive. There is a name for it's type, but it escapes me right now. It's a twin bogie thing, with driving wheels and steam cylinders on each end. On one bogie sits the coal tender and on the other sits the water, with the massive boiler slung between the two. I think this layout was developed originally for use on welsh narrow guages so a more powerful unit could negotiate the twists and turns. However, this was a full sized monster, and I do recall that it had a brass plate on it from the south african railways.
You would only design and build something like that for the power it could give, which was the inspiration for my original post. which was why not use a triple expansion on rails. Size for size they would give a considerable improvement on single or even twin cylinder models.
A serious piece of kit. Obviously built for sheer power. Now think what it could have done with a triple engine at each end instead of those cylinders. Each engine directly driving an axle, and that axle linked to the others on the bogie by connecting rods.
Certainly complex, but no more so than some I have seen. Plus, for the same power output, more fuel efficient, surely important to railway operators, a notoriously tight fisted bunch.