On 2011\05\13 13:30, Roland Perry wrote:
In message , at 13:00:34 on
Fri, 13 May 2011, Basil Jet remarked:
If the lift had doors on two sides and sensors to detect people
within, a single lift could link the street, the ticket hall and the
platforms without compromising the barrier line.

With doors opening alternate sides I suppose.

The lift would have two modes, streetside and airside, and could only
switch between the two when empty. On the ticket hall level the mode
would control which of the two doors opened.

And I predict it would spend most of its time full of people wanting the
opposite mode to that which it was currently performing, and refusing to
get out.

It's theoretically possible that one mode could hog the lift, but I
don't think any lift on LU is busy enough for that to happen, except at
the lift-only stations such as Covent Garden.

The other way to exploit one shaft and motor would be to attach two lift
cages on top of each other, with the top one streetside and the bottom
one airside. If the distance between the two cages was the same as the
distance from street to ticket hall, they could both load simultaneously
at the top, although they'd need to load separately at the bottom. That
way neither mode can hog the lift, but people would often be in a
stopped lift with the doors shut.