David Cantrell wrote:
Why is there no in-station interchange (perhaps via a gateline, like
at Richmond) using a tunnel at Shepherds Bush between the Overground
and the Central line? Cost, I suppose, but it would be a very short
tunnel, and I can't imagine that there's lots of buried
infrastructure there.


I think the biggest issue is the relative geometry of the existing Central
Line platforms. Access is 'end fed' onto the two separate platforms at the
west end, (entry on one platform and exit from the other) but the two
running lines are effectively alongside each other by the far east end; so
the space available for additional stairs and a lift to/from the level of an
interchange passageway is reducing, the further to the east you get.

There was a plan somewhere online of how they'd provide interchange access
to the platforms but I wonder if it was binned because they couldn't make a
silk purse out of a pig's ear. I believe a future capacity upgrade may be
necessary but could mean serious rebuilding - with one or other platform
relocated outside the tracks, in a similar way to some of the Northern line
'islands'.

There were capacity issues on the day the shopping centre first opened IIRC,
but I guess it has settled down now - unless anyone knows differently of
course...

Paul S