Neil Williams wrote:
On Fri, 21 May 2010 17:48:44 +0100, "Paul Scott"
wrote:

Not at all likely as [IIRC from discussions in uk.railway] current
mainline stock door controls only allow opening on one side.

Really? I'd be surprised if you couldn't open both sides
separately[1]. Unless the "close" buttons close all doors regardless
of size, in which case you'd need more staff to watch the "wrong" side
when closing.

[1] You definitely can on 321s, as these can often be seen in
Bletchley CS with all doors open on both sides, presumably during
cleaning.

Yes - in the general case I think it's probably to do with a single guard or
driver (when in one man operation mode) only being able to sight one side
clear at a time, but I'm sure we've also been told here before that on stock
like Desiros or Electrostars the position of the guard's key defines the
only side that will open.

Of course that may be overidden in depots somehow.

Paul S