"Pyromancer"

I can see the advantages of this on very long freight trains, even with
continuous brakes there must be a lot of slack in a mile long train, but
your later post said it was common on passenger trains too - any idea
why?

Because North American passenger trains have slack.

Also permits some leeway when travelling really slowly to a stop, you can
keep the train rolling without having to release the brakes to travel that
extra say 20 feet to the correct stopping point.

I used to power brake even with a trains of two passenger cars and even with
the doodlebug, a pre-war railcar. Mid you, in these cases it was power
braking with the throttle in notch one.


--
Cheers
Roger T.

Home of the Great Eastern Railway
http://www.highspeedplus.com/~rogertra/