edwin_m
Veteran Member
Before Cambridge North I would have said that UDUD was the clear choice, because most of the trains approaching via Audley End would have terminated at Cambridge (central) and many of those approaching via the Royston line (on EWR or from KX) would continue beyond. So a couple of new eastern platforms, potentially single ended, could be built for the Liverpool Street terminators and most of the flows would be separated. Now those terminators go through to the North station it's probably a case of doing some operational simulation on the layout and future timetable, to work out whether the cost and disruption of a grade separation for UUDD is justified. As the timetable isn't known, it's too early to do that, hence also too early to make any costly assumptions about what the layout will be.The primary argument for EWR to come in from the south is to continue on to Ipswich as a through service. Services terminating at Cambridge aren't going to go down very well with the eastern section folk who have been campaigning for the line for decades, so I'm not sure how relevant the bays are to EWR. Presumably their existing conflicts are part of the reason for running services through to Cambridge North now?
(Apologies in advance if my information is somewhat out of date, I haven't been through Cambs for quite some time), but yes, the bays at Cambs used by the 8-car terminating services are unfortunately off to one side. Presumably given sufficient new through platforms they could be abolished, though, with terminating services using the central through platforms effectively as double-ended terminal platforms. No conflicts then. North of the station everything merges into 2 tracks anyway, so no conflicts there, and you only need a smaller single-track flyover at SBJ as well. Not sure how many platforms you would need at Cambridge station for that sort of arrangement though.
I recall when I used to commute through there musing if you could jack the listed building up and shift it away from the railway enough to convert the bays into through linesI doubt it would fare well given its age, but stranger things have happened at sea.
Having UDUD means you will get passengers at Cambridge South having to change platforms at short notice as their next train could depart from one of two platforms, so unless you designing it so they're waiting on an overbridge or being very strict with the timetabling so the same services always call at the same platforms, you will get all sorts of undesirable flows as people move between platforms trying to speed up their journeys.
From Cambridge South, only passengers for Cambridge (central), Cambridge North and possibly Ely would have a choice of platforms if Cambridge South was UDUD with no trains routinely switching tracks south of it. So not many people will need to make short-notice platform dashes, and this happen when someone wants to catch one a few minute early rather than because the train they actually need to catch has been re-platformed. UUDD does however have the advantage that someone travelling say Stansted to Lynn or Ipswich wouldn't have to cross the bridge at either station.
