Relay question

[tony duell]

> I had a 3-Rail Hornby "O" gauge that used a toggle relay to reverse. I think
> rather than over voltage it was set up so the relay had a very low "hold-in
> voltage". It had a pawl that drove a commutator shaft that generated the
> reversing. I think it was 24volt but might have been higher....

Sounds like the one I was describing, except that the relay coil was 
the motor field winding with the moving pole piece acting as the
relay armature. The switch was a fibreboard disk with brass contact
plates on it and 3 spring contacts pressing on it. The fourth connection
was made via the pivot screw to the chassis, then to the wheels and back
to the track. I still have the motor unit somewhere, it'll turn up in the next 
year or so as I unpack everything..

IIRC it was 20V AC

-tony