If and when EWR comes to fruition the line between Didcot and Swindon should be four track. How difficult would this be to do now or in the future?
The
GWR▸ (the original one) had a programme to do this in the 1930's. The sections from Didcot to Milton, Wantage to Challow and from Shrivenham to Bourton were quadrified (to borrow a term from FTN) then.
Land was purchased for much of the rest in the 1930's (all the way to Wootton Bassett Jn).
The pinch points will be the A34 underbridge at Milton, Steventon (where the line goes through the village); A420 overbridge (Acorn Bridge) nr Bourton, and the A419 underbridge at Stratton.
There are some significant embankments between Steventon and Wantage that will need widening and quite a deep cutting at Uffington. The cutting at Grange Drive in Swindon is quite deep, but the proximity to the houses might be an issue here.
There are also a few listed bridges on the route.
This is all from memory so other please correct if my memory is not correct
That's interesting, thanks. I was unaware of the (original) GWR widening programme. They did get as far as quadrupling Wantage Road to Challow (which was removed in the 1960s MAS resignalling scheme, then reinstated in 1990!) as well as adding/lengthening other loops on the section. I wonder if
NR» still own the land that was purchased?
As you say the pinch points to widening the line will be Steventon (it's already four-track under the A34 bridge) and NR is making no provision for more than two tracks with its replacement design for the Steventon High St overbridge. From Causeway crossing to Wantage Road should be fairly strightforward.
Further west, in addition to the cutting you mention, there are houses in close proximity to the line at Baulking and Uffington. Also widening the track on the approach to Swindon would be very expensive. Don't see it happening anytime soon unfortunately.