Last night (16 July) Chiltern Railways gave a presentation and
question/answer session about their plans for a new interchange station at
West Hampstead, which I went along to.

Main points:
* Platforms for Chiltern, Met and Jubilee lines, Silverlink and Thameslink
(and possibly Midland Mainline). This would give direct access to hundreds
of stations -- including non-stop to Marylebone in 3 minutes.
* Linked by a walkway. This would pass over Chiltern, Met, Jubilee, then
duck down in an escalator to carry on at a lower level under West End Lane
and the Silverlink and Thameslink lines.
* Main ticket hall and street access more or less where Silverlink station
is now, but access to/from street at both ends of the walkway.
* New, constant, vertical alignment of West End Lane between Travis Perkins
and Broadhurst Gardens (i.e. all the railway bridges would have to be
reconstructed). West End Lane would also be wider at this point, allowing
room for buses to stop without impeding traffic.
* New development on land on either side of WEL at this point, though
probably limited to 4-5 storeys.
* Bus/taxi/bike only access between the new West Hampstead station and the
O2 centre (via a road more or less where Blackburn Road is now, and
presumably joining up with the access road to the north of the O2 centre)
* No public funding required. This is a point in this proposal's favour,
as previous ones have been either reliant on public money, or have had to
include massive development to recoup the cost.

They said that if all goes well on the planning side, the interchange could
be in and working by the end of 2009 (which sounds a tad optimistic to me).
All the TOCs involved seem enthusiastic, as does TfL, and the SRA (which
is important because Silverlink/Thameslink/MML's franchises come up for
renewal before 2009).

Chiltern said they would put some plans up on their website over the next
few days/weeks.

Hope this is of interest.
--
Tom Sutch