Does it though? From a quick look at the map (and a slightly less quick look at Google Earth) it seems to me that there are three 'entry points' to the west of Manchester and five 'exits' to the east.
Entry
- Salford Crescent
- Eccles (Chat Moss route)
- Trafford Park (Warrington Central route)
Exit
- East Didsbury (Airport/Styal route)
- Stockport (multiple routes)
- Ashburys (Glossop and Marple routes)
- Ashton-under-Lyne (TransPennine route)
- Rochdale (Todmorden route)
Still looking at the map (and Google Earth), if one wants to seperate trains arriving through Salford Crescent from all other services, you can do that by going through platforms 5 and 6 at Manchester Victoria and heading up to Rochdale/Todmorden. Sending trains from Salford Crescent to Ashton-under-Lyne (via Manchester Victoria) means interfacing with any trains from the Eccles direction that are bound for Man. Vic. and beyond. Finally, sending Salford Crescent trains to any of the other three 'exit points' mixes them through Castlefield, yet option C has 4tph (2x Blackpool, 1x Cumbria, 1x Scotland), plus a peak Southport, that I understand would do exactly that. Route pairings to avoid all interfaces would be as follows:
- All trains from Salford Crescent would proceed towards Rochdale through Man. Vic. platforms 5 and 6 as described above
- All trains from Eccles would proceed towards Ashton-under-Lyne through Man. Vic. platforms 3 and 4
- All trains from Trafford Park would proceed towards East Didsbury through Castlefield
- All trains towards Stockport would depart from high numbered platforms (except 13 and 14) at Manchester Piccadilly
- All trains towards Ashburys would depart from low numbered platforms at Manchester Piccadilly
Option C doesn't do that so I don't think it is separating train movements to the fullest extent possible. It seems to me that Salford Crescent - Deansgate is the worst conflict of the lot (given that it is crossing the Eccles-Victoria route and not just merging in as the other conflicts are) and yet option C retains such moves. Am I missing something?
Obviously completely seperating services is unecessary and could have a massive impact on availablity of direct services (plus at least three sections of track in central Manchester would have no trains using them, and neither would Man. Vic platforms 1 and 2), so a compromise needs to be found.