Are we tackling this question from the wrong end - do we not have to also consider how to segregate trains to reduce conflicting movements?
Integral in rebuilding Preston station for readiness for HS2 trains will be rebuilding the junction/junctions on the approaches to Preston. Euxton Junction has been improved from being a single lead junction and Lancashire County Council have long term aspirations for a non conflicting junction. This obviously did not make the cut when the current electrification plans were put in place but was it the case that HS2 was then scheduled to by-pass the existing station?
By sorting this junction out we would end up with Preston station being spilt into three-ish segments - (a) North West Local Group - Manchester,Blackburn,Liverpool,Ormskirk to Blackpool (b) HS2/WCML to Scotland, Barrow (c) freight through lines - do these need a dedicated
route(s)? - If so, do freight trains have to be stabled before passing through the station? Should extra goods loops be built north and south of the station and if so where?
Major route switching would then take place at Maudlands Junction, where all trains have to slow as they enter/leave the station approaches. Another design consideration is to whether "join and divide" as formerly practised by TPE will be revived. The Castlefield choke point may well prompt reconsideration of moves to save paths through Manchester.