"Roland Perry" wrote in message
...
In message , at 11:00:51 on
Thu, 15 Jan 2009, Peter Masson remarked:

I envisage an underground terminus, possibly double ended, with one
entrance
from the concourse at St Pancras (near the access to the Thameslink
platforms, and another with an entrance from Euston (may need a
travelator).

What would it be "underneath", there's a lot of existing stuff under StP
and KX, and I'm not sure you'd be able to locate anything under the
British Library.

Put it under Phoenix Road/Brill place, behind the British Library, so at
right angles to the Thameslink platforms.

The suggestion of reversing the Kent domestics at St P, and extending them
to Heathrow, has some attractions, but the rolling stock you need is not
really compatible (Kent domestics a lot of seats for commuters; HEx plenty
of luggage space, and a high quality first class section. Also, the St
Pancras throat is now very congested with tracks going in all directions,
and I'm not sure how an exit that has to turn west will work.

I really can't see how a HSL from St Pancras, or more likely Euston as
that's the only obvious space for the terminus, via Heathrow, will work. It
would have to be in tunnel at least pretty well all the way to Heathrow, and
with a stop there is only going to be marginally quicker to the West
Midlands than going at 125 mph down the WCML. The Greengauge proposals (head
out of London via Northolt Junction, and follow the general alignment of the
Chiltern Line/M40, serving Heathrow with a branch, joining the main HSL in
the vicinity of Denham) seem to me to be more rational.

Peter