On Thu, 3 Apr 2008 21:15:19 +0100, Tom Anderson
wrote:

On Thu, 3 Apr 2008, Tristan Miller wrote:

What is the purpose of the "open" buttons on the doors of the London
Underground carriages? On every Underground train I've used, the doors
open automatically at every station. Is/was there a time or place where
they don't open automatically and the buttons must be used?

Yes - the past. It used to be the case, AIUI, that the driver didn't open
all the doors when the train stopped at a station on the surface, at least
if it was cold and/or wet and not too busy. Then, you'd have to push the
button to open the door. However, this seems to have been too confusing
for passengers, and now all doors always open all the time (except when
they don't).

I recall when I first came to London (Autumn 1997) the District line
trains had driver-controlled doors in the summer and
passenger-controlled doors in the winter. I don't recall how
summer/winter were differentiated; possibly by GMT/BST? In any case,
it only lasted a couple of years.

I have heard two possible explanations: one (as you stated) being that
passengers were confused; the other being that there were fears of
passengers using close-door buttons to close the doors on other
passengers.