Tim Roll-Pickering wrote:
How wide are the islands though? Leaving aside the shops on those platforms,
the available space for moving down them is so narrow that most of the time
passengers need both sides to move down, especially if you're trying to get
round a buggy. And how exactly would you construct a TfL users only sealed
route from the eastbound Central Line to the DLR platform?

Fairly wide. These should give you a rough idea:

http://www.flickr.com/photos/triborough/92363857/
http://www.nycsubway.org/perl/show?22191

--
David of Broadway
New York, NY, USA