Commuter wrote:
Sorry - not sure exactly what they're called, but why is it only the
SSL and Overground that are to get trains that you can walk all the
way through (like a bendy bus)?

Is there something on the Tube lines that stops this design being
practical?

http://www.google.co.uk/search?hl=en...G=Search&meta=

Note that the Vic Line was built after the "wayleave" concept was abolished,
so has graceful curves which make no attempt to stay beneath streets. I
don't think walk-through trains could ever be considered on the earlier
lines. The Jubilee Line uses fairly old tunnels from Baker Street to
Finchley Road, so I'm not sure about that one.