On Thursday, 6 August 2015 13:55:28 UTC+1, Recliner wrote:
Yes, I suppose so, though at least HS2 will now be in tunnel in the
Park Royal area, rather than taking over that old GWR Oxford line
alignment to Northolt.

But once Crossrail and the OOC station are built, I wonder if a
possible route to Paddington with available capacity will remain?

Think laterally - what'll be at OOC station? Yup, Crossrail & a connection to LHR. Won't that be enough to attract Chiltern?. Quite probably, with no requirement for Paddington.

Also, someone up-thread suggested Risborough/Aylesbury - why not extend that northwards & eastwards when the new EastWest comes online & run to Milton Keynes or Bedford? That's my thinking.