On Sun, 16 Nov 2008 06:19:01 -0800 (PST), MIG wrote:

Announcements like "This train is ready to depart, stand clear of the
doors, mind the doors, mind the doors" are pointless and irritating,

Yes, very pointless. Particulary since the spiel is so long that
anyone with more than a couple of days' rush hour experience knows
that "This train is now ready to depart, stand clear of the doors..."
really means "There is plenty of time until the doors close, continue
boarding."

Particularly when it starts happening while people are still queuing
to get off and the people on the platform are politely standing back.

I've noticed that on the Central Line, the doors generally don't close
at this point, while on the Northern Line they do, leaving people on
the platform (both based on experience at Bank), so the interpretation
may depend on the circumstances.

I've had similar experiences at Waterloo on the eastbound Jubilee in
the a.m. peak. The doors close as soon as everyone has finished
getting off, meaning you only get a chance to board if few enough
people get off from the door you're waiting at. However, people don't
tend to stand back to allow people off the train (possibly because
they can't due to the density of the crowd around each platform edge
door) - the first person off has to practically push and shove their
way through the crowd, opening up a narrow route for the rest to
squeeze through.

The result is that each train departs with a fair share of fresh air
on board. Meanwhile, upstairs in the Jubilee ticket hall, the ticket
gates are closed and the entrance from the NR concourse is shut,
because the platform is overcrowded...