MK_Tom, I'm fully in support of an additional station on the HS2 route, as some may know, I'm also an advocate of 4 track between OOC and Birmingham Delta, and a station to link with EWR and roads in that area would be a very nice addition.
And to back deltic, Manchester and Leeds need City Centre stations, the major railhead is Piccadilly and Victoria (And to a lesser extent, Oxford Road), and in places that are rather large cities, car ownership tends to be quite low among the members of public that are likely to travel longer distances by rail.
Most professionals that live and work in Manchester do not own their own vehicles, so the point 0 travellers need the CC penitration.
As do connecting travellers from all over the Greater Manchester Urban area, they will travel to Manchester and change onto the HS services.
There does also NEED to be at least one parkway for Manchester though, and Leeds for that matter (but I don't think it should be at Cross Gates, it should be at the junction, so somwhere just south of Wakefeild, or possibly, depending on the alignment chosen, near Oulton and Castleford)
Manchester could quite well live (and would be justifiable to have) two parkway stations, one at Manchester South Parkway, between the M56Spur for Manchester Airport and Wythenshawe, basically serving Manchester Airport and Cheshire (Completing the A555 and calling it the M60 would help too) and Manchester West Parkway near Culceath north of the Ship Canal, round about the area to the North of M62 Junc 11 at Birchwood, this would connect initally (and continue to) into the Chat Moss Line for the WCML and Liverpool, and when the HS2 network is continued further north, it will be done from here. There would then be the chance to use this new alignment to take commuter traffic off the M62 and M56 and put them on a Park & Ride HS Rail service using Javelin style units, operating at up to 6tph (as these areas within the Delta Junction Area) would be 4 tracked.
Manchester West Parkway at Culceath would also serve as a London P&R Railhead with services to London calling there, as would Manchester S Parkway for Cheshire, so the areas with high car ownership, in the rural areas would have excelent services to Liverpool via Chat Moss from Manchester W Parkway, and to London and Manchester from both Mancheter W and S Parkways.
Would also take a lot of strain off of the Castlefeild Viaduct through Oxford Road and Victoria by taking the fast Liverpool and Scotland services off of the Chat Moss through Paitcroft, and onto the HS2 tracks out of Manchester, albeit potentially at conventional 125 speeds, out to Manchester W Parkway (Would need ERTMS2 fitted stock), then joining the Chat Moss or WCML to continue. (I would have all intentions of forever keeping this link in place for this very purpouse) Fast TPE Services would continue to run via Chat Moss as Inter Reigonal services, or divert back via Guide Bridge again and into the HS2 station area's conventional platforms to access that route, proberbly keeping them on the Chat Moss as there is little time gain.
Note: This is based on a 10 platform HS2 station in the Baring St Industrial Area, with access to Manc W and S Parkways via an exploded Delta Junction, fully segrigated access at 125mph linespeed, ERTMS2.
So service patterns involving these stations would look like...
CAP = Captive Stock
CC = Classic Compatable Stock (As ordered at HS2a)
SSE = Standard Stock ERTMS Fitted (125mph capable)
SS = Standard Stock
CAPC = Captive Commuter Stock (200m long 'Javelin' style units, but at EU Guage)
In and out of Manchester Baring St
3tph Manchester S Parkway (CAPC)
3tph Manchester W Parkway (CAPC)
1tph Scotland via Manchester W Parkway (CC/SSE)
2tph Liverpool L St via Manchester W Parkway (CC/SSE)
2tph Birmingham N St (CAP)
3tph London Euston (CAP)
1tph Tunnel via Birmingham Parkway and OOC (CAP)
Between Manchester S and W PW (Note: Some of these may be joined for portion working, for example, the via Preston services could be joined to each Liverpool and divide at Manchester W Parkway, 200m of train to Glasgow or Blackpool or wherever, and 200m of train to Liverpool, if Glasgow needs it, 400m just for Glasgow, calling only Preston and Carlisle)
2tph Euston - Liverpool L St (CC)
1tph Euston - Blackpool N (CC)
1tph Euston - Glasgow Cen. (CC)
Anything else going up the WCML North
1 - 2tph Birmingham - Liverpool L St (CC) (Possibly join with Manchester Diagrams)
1tph Birmingham - Scotland (CC)
And these services:
Euston - Chester - Holyhead
Euston - Liverpool via Runcorn
Will leave HS2 at Rugley for Crewe...