> May I offer an idea?
>
> I think, from what I understand, that compressed air is distributed to all
> the cars.  Couldn't each car have an air tank that stores the compressed air
> and, upon a signal from a PIC, cause breaking action?
>
> Just a thought,
> Max

That system's already set up so that, when/if that compressed air pipe
is vented to atmospheric pressure, the brakes are applied.

Designed this way intentionally (Brakes are, by default, LOCKED, until &
unless there's air (steam originally?) pressure in that line, so rail
cars sitting on a siding etc. don't move much unless & until you attach
pressure there (as you attach to an engine.)

(Thought of using said air pressure to power up a PIC, on connection of
the car to the train;  unsure if the system has capacity for enough
pressure/volume to do this.  Are we getting well off into fluff-land,
yet?)

  Mark