On Wed, 2 Dec 2009 10:38:04 -0800 (PST), MIG
wrote:

But it seems that if the key comes out, the door reverts to being a
normal door and closes, and the train takes off without further
prompt.

That seems somewhat of a dangerous[1] design flaw.

Arguably, if the key is removed the unit should remain in the state it
was in (one door open) until it is reinserted and the member of staff
tells it what to do next.

A command to depart should be active, not passive.

[1] Let's say the member of staff does get themselves locked out - but
in doing so gets their coat caught in the door. The train then takes
off for the next station, whacking the member of staff against the
wall if a passenger hasn't noticed in time.

Neil

--
Neil Williams
Put my first name before the at to reply.