On Sat, 16 Jul 2011 12:21:22 +0100, Clive
wrote:

In message , Charles Ellson
writes
Neither the 38 or 62 stock that I worked on had any kind of interlock to
cut power if any door was open.
AFAIR the only interlock was (allegedly) with the guard's bell.
There was no interlock, the doors could be opened at any time, any place
without affecting traction current to motors or anything else.

.... except the guard's bell. When the guard was still located within
the passenger compartment you would often see one digit on that button
at the same time as or before the door close button was being pressed
by another digit (not to be confused with the use of two buttons to
open the doors). If the doors failed to close properly then the driver
did not get the bell.