A thought perhaps if all trains stopped at Manchester Piccadilly HS2 station and Manchester Airport HS2 station would they need to be built for HS operation?
Whats the top speed that is likely to be achieved between the two anyway? 100, 125, 140mph?
Surely that would dictate what kind of curve could be tolerated on this section as I would suggest HS2 needs to fast west / east rather than north to south at this point and allow fast service from Crewe and Manchester Airport towards the eastern flank of NPR towards Leeds / Huddersfield / York / Sheffield as it were.
None of the city sections are specified any higher than 230km/h. However, they are set to be GC loading gauge and isolated from the rest of the rail network for reliability. Most, if not all, possible NPR or Midlands Connect (or whatever it's called) routes don't need to be any faster than 230km/h. The only sections of line which need to be faster than that are the mainline routes, as otherwise they'd be no faster than the WCML or ECML and that removes much of the value of building them. For the western branch of Phase 2b, it's easy to build a 300km/h+ mainline route and then 230km/h branches off of it to Liverpool and Manchester. Any new TransPennine route could be 230km/h, and anything north/east of Leeds or York would be 230km/h max as well. The main conflict is then on the eastern branch, since the towns and cities along this route follow a different population/travel pattern which makes them less unsuited to slower running with with more frequent stops. A Birmingham to Derby/Nottingham, D/N to Sheffield or Sheffield to Leeds service should really run at 230km/h, but that makes them less suited to running on a new line optimised for 300km/h+ as has been planned so far. Building two lines isn't a good idea, but having long stretches of mixed-speed running might not work either - it just depends on the proposed timetable. Mixed-speed 230km/h and 300km/h running works on HS1 but that's a relatively low-traffic railway. A better comparison may be with the Neubaustrecke in Germany, which see a mixture of 200km/h classic and 250km/h+ higher-speed services.
Starting to stray into speculative territory, but it feels like Manchester to Scotland isn’t really being considered. NPR is concentrating on East-West, the Terminus station handles going South, but what about going North? I realise there isn’t much HS2 track for it to run on, but in terms of having an equivalent service and not needing to use platforms 13/14.
There's two things here. Pure Manchester to Scotland expresses after there's significant high speed running north of Preston would probably work fine going to the Airport and then terminating at the HS2 Piccadilly station. With a massively reduced journey time an hourly HS service from Glasgow or Edinburgh using a 200m HS2 unit would probably work fine. However, the current TPE service to Scotland also acts as the express service from Manchester to the other towns and cities in Lancashire and Cumbria which would not be included on any new HS routes to Scotland. For instance, you'll have express regional trains from Carlisle (via Oxenholme etc), Lancaster, Barrow and Blackpool needing to get to Manchester too. Should these continue to clog up the route via Bolton and Salford Crescent? I don't think so. I think we'd be better off with an NPR network that covered both Liverpool-Manchester and Preston (and hence WCML) to Manchester. If you serve Liverpool with the minimal extra track on top of HS2 going via the Airport dogleg, then your Preston/WCML destinations are disadvantaged and they'd probably still end up going via the current route. I think a straight-line route from Liverpool to Manchester roughly following the Chat Moss line, and then having a complex junction set where it crosses the HS2 mainline, would serve that pretty well and allow the existing Mancunian rail network to be handed over to purely local/regional services.
