HS2 are proposing an interchange between High Speed 2, Crossrail, and
all services out of Paddington (including the Heathrow express), at
Old Oak Common.

But there's also the possibility of

(a) the West London Line
(b) the North London Line
and (c) the Central Line

serving the new station. Old Oak Common could become more important
than Stratford or Clapham Junction.

HS2 don't seem to have investigated (a)-(c) yet, but they are shown as
possibilities in the government command paper.

What are people's views on how plausible these extra interchanges are?
I don't know the area well myself.

The West London Line would be particularly useful for the link with
Clapham Junction. But I imagine there would be dangerous overcrowding
with the current level of service. How much scope is there to upgrade/
get the freight off the route if it became a priority for investment?

It would also only be one stop from Old Oak interchange to Willesden
Junction, for the Bakerloo and West Coast Main Line.

Layout of proposed station (page 83):

http://www.dft.gov.uk/pgr/rail/pi/hi.../chapter3a.pdf

(The top platforms are HS2, bottom ones are Crossrail/Great Western.
The Central Line is shown in red in the bottom left, the NLL is shown
in orange on the left and the WLL is shown in orange on the right.)

Satellite view of the site:

http://maps.google.co.uk/maps?hl=en&...-8&sa=N&tab=wl

Diagram of the possible interchanges on p107 of the DfT white paper:

http://www.dft.gov.uk/pgr/rail/pi/hi...pdf/cmdpap.pdf

(cross posted to uk.railway and uk.transport.london)