European Railroad Discussion > Prussian P8 dampflok cab question

Hi, I've been enjoying the many YouTube videos of German steam engines in action. On a couple of cab rides inside the P8, the engineer is mostly adjusting two controls. One is a handle and levers featuring two parallel brass bars mounted on the boiler -- this appears to be the throttle. Another is a wheel on the end of a long worm screw mounted horizontally on the engineer's side. What does this control?

Geoff

That's the reverser. I believe a few US railroads had locomotives with a screw reverser. It adjusts the cut off.

Jim Maurer

Thanks! Would there be a reason for the engineer to adjust this while the train is moving?

gherrig Wrote:
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> Thanks! Would there be a reason for the engineer
> to adjust this while the train is moving?

Yes, the speed and power of a steam locomotive is governed by how much steam is admitted to the cylinders and how expansively it is used, a driver can adjust the cut off as well as the regulator to take account of changing circumstances on the road, gradients, recovering from speed checks etc. Reading books on locomotive performance it is fascinating how drivers techniques for coaxing power from a steam locomottive differed, some would set the cut off and drive entirely on the regulator, others would consistently adjust both, or simply adjust the cut off. I guess that's why steam locomotive drivers had such a mystique about them, they were almost artists rather than technicians :-)

86235 Wrote:

I guess that's why
> steam locomotive drivers had such a mystique about
> them, they were almost artists rather than
> technicians :-)


Thank you for that statement. I have always held that steam locomotive operation is an art. At least I thought that of the operations I was involved in.

Bob Krieger
Cheyenne, WY