Having travelled over the route a couple of times again recently and enjoying watching real time movements using the likes of East Anglia Signal Maps, (who needs train sims when you can watch the real thing in real time!) the infrastucture is pretty much at its limits these days, (as acknowledged in NR's GEML Study published in July). The increase in liners from Felixstowe since the Trimley doubling seems to have moved the pinch points further north (and west). The single lead junction at Haughley and the long(ish) signal sections constrain operations. I didn't realise until recently that until a train is pretty much in the platform at Stowmarket a second cannot be signalled off of the Bury line at Haughley. Add in any minor disruption and delays can snowball. Haughley Junction re-doubling is in NR's Study but it is not yet funded or programmed so is a good few years off yet. Though with the closure of the factory on the land adjacent to the up side of the track here makes me dream of a flyover to grade seperate traffic! Whilst NR's study does mention grade seperation, the suggested intervention proposes simply restoring the former double track layout for parallel moves. So I doubt grade seperation will ever happen even though it services one of the most valuable freight routes in the country, I suspect it will become yet another housing estate and an opportunity will lost for good!
Interestingly hidden in the report is the aspiration for an hourly Norwich in 90 service, though this and other aspirations can only be achieved following the completion of the series of improvements including in the document, namely;
* Bow Junction remodelling,
* Beaulieu new station (though only a 3 platform layout with centre turn back/overtaking road. i.e. no dynamic loop(s) for overtaking freights or slower passenger services),
* Bizarrely a new down loop at Marks Tey, utilising the Sudbury platform and
* Haughley Junction doubling.
To cope with longer term growth 3/4 tracking Shenfield to Chelmsford and Ipswich to Haughley Jn is recommended, as is Trowse bridge doubling.
I'm surprised that no mention is made specifically of Digital Signalling, only closing up of signals and reductions in headways, even though Bow Junction remodelling is claimed to deliver up to 10 extra trains an hour (where?) - 30 trains per hour between Bow Jn and Shenfield - surely not deliverable with conventional signalling and the mix of stops and traffic types in the peak?
The suggestion of a new route from the 'London' area via Stansted to link up with the GEML north of Witham was made by Greengauge 21
http://www.greengauge21.net/wp-content/uploads/Beyond_HS2WEB-1.pdf when it looked at where next for High Speed Rail after HS2, though this is likely to be as probably as Haughley grade separation!