When some of the W trams were refurbished for the City Circle services they
were fitted with a deadman device on the controller, operation similar to
that on a traditional electric train, in that the handle had to be pressed
down while in operation, otherwise the power would automatically cut off
and the brakes apply. It was intended to use these trams one person
operated, but this hasn't eventuated, although no fares are collected an
attendant rides these trams. As far as I know most of the W's, except the
Circle Line fleet and some additional ones kept in reserve for the Circle
Line, still don't have deadman facilities, so the driver could easily take
his hands off the controller and the tram would keep going.
Sydney experimented many years ago with a deadman device on its trams, but
it only cut off power and didn't apply the brakes - not much use going
downhill!!
Brisbane had emergency brake valves in the passenger saloons - passengers
or conductors could thereby stop the tram (but not cut off power).
David Bennetts
Canberra