On 12 Jan, 17:16, Jarle H Knudsen wrote:

On Mon, 12 Jan 2009 07:37:46 -0800 (PST), MIG wrote:
As well as from each doorway, they can also operate the doors from the
front of the train. Sometimes it may just happen to be convenient,
and sometimes, eg at Canary Wharf, they need to be able to use the
mirrors to see both sides.

Can't they just close one side at a time?


Yes, but at peak times timing is everything - and the vestibules get pretty
packed too, so even moving from one side to the other is a challenge.
Perhaps the same thinking applies to some extent when riding at the front in
other places, where station platforms may be at either side of the train.