I actually meant to use the five platforms at Waterloo and the eight at Paddington to run a 20TPH combined frequency west of OOC. Not ideal of course to split stations, but beggars can't be choosers. Would it be better to only serve the 'traditional' destinations from each termini? I'm not sure....
It is IMHO quite possible to extend platform 1 at Paddington to 415m, possibly island platform 2&3 as well (possibly at the expense of one of P4-8). Those three platforms could service most / all of the 6TPH HSR to long-distance destinations on the Western.
If 400m HS trains were to run on the Western I would envisage splitting them at either Bristol Parkway or Temple Meads. No-where else has room (except maybe Newport).
Anyway, perhaps all this western/south western HSR stuff should be on another thread?
Shall we separate the two routes?
Since we are spending the nation's capital without limit, shall we just have the GWML High Speed line start from Paddington HS platforms, calling at Old Oak Common (on the current IEP site)?
On that basis, build your desired tunnel from just west of OOC to the edge of London, and use it for main line services in the short term.
Then build something else entirely for a SWML High Speed Line out of London? Starting from Waterloo HS platforms where the Eurostar platforms were?
The cunning plan on the CR2 thread (I think) to tunnel the SWML fast line under Wimbledon could be used for that route, perhaps?
(pic: Ben Brookesbank)