philipmartin wrote:The fireman operates it. A steam engine without a fireman: that doesn't sound like a good idea to me.
As you say, the fireman operates it. The fireman has other tasks, including maintaining the level of water in the boiler and double-checking the signals with the driver, so it's not a steam engine without a fireman.
I've operated mechanical stokers on the South African 15F, 25NC and GMAM classes. It's basically a screw or worm gear that brings coal from a trough under the bunker to just below the firehole door, where there are adjustable jets of steam to blow the coal to where you want it in the firebox.
Mechanical stokers certainly save you a lot of muscle power, but they are tricky beasts. You have to keep your eye on them otherwise you suddenly find steam dropping off and a mountain of unburnt coal in the wrong place. They seem to have been designed for optimal running at high speed with heavy loads, and you can achieve a nice steady thin fire which looks almost liquid. But when you're running slowly with light loads you often find that you can't run the stoker slowly enough (it keeps stopping) so you have to keep switching it on and off. You also have to watch out for jams. There are times when you have to fire by hand, eg when it jams, when running very slowly, when shunting, and packing the back corners of the firebox before a journey or before a steep uphill gradient. When you do have to hand-fire a mechanically-stoked loco it really is a bugger, as the firehole is at the wrong height, the firehole door gets in the way (it's a flap rather than the usual sliding doors) and the stoker itself prevents you standing where you really need to stand for firing.
One night I got called out with another fireman to relieve a crew who had had to hand-fire a mechanically-fired 15F all day because the stoker had jammed with fine coal dust which had become a solid mass; the loco also had a leaking tube. Driver, fireman and pilot (who happened to be an old steam driver himself) all took turns at firing. They were absolutely knackered. The two of us then spent the whole night on our hands and knees in the bunker scratching away at packed-coal dust, then running the stoker until it jammed again, then scratching away some more. Finally, by the time the crew booked on again next morning, we were able to hand them a loco with a working stoker, much to everyone's relief.
