If it goes ahead, Network Rail planning is for a blockade between Evesham and Moreton-in-Marsh - not clear on the duration, but it won't be short - simply because that would be the most efficient way to deal with this section, both due to its length, but also because there are long stretches where, when continuous welded rail was laid, the track was slewed across to the middle of the formation, so it's not just a question of dropping the new track alongside. This is less of an issue Ascott-Charlbury, where work could be done at weekends or in short blockades.
Looks like a Worcester-Evesham rail shuttle - Honeybourne is probably out (buses here?) even when work is nearer to Moreton, as the remaining sidings would be a logical base for engineering trains - with peak through London trains from and to Worcester, running via Cheltenham and Stroud. If the hourly FGW▸ /LM▸ Gloucester-Worcester service gets started from December, then that would be able to offer connections the rest of the time.
An Evesham-Moreton bus link would make sense, but going through by road to Oxford, unless there are no trains south of Moreton, takes forever.
While an Oxford-Moreton shuttle would look logical off-peak, I think some through London services at busy times will be needed, in addition to the 05.50am ex-Moreton.
This would maintain passenger goodwill but also avoid extra operating complications at Oxford, where dealing with yet more empty stock and passengers moving around the station at busy times isn't an attractive prospect.
I'm sure a competent timetable planner could come up with something workable without too much hassle and the shunting operation to move between the platforms at Moreton doesn't involve entering the Evesham section.
"It won't be short" - if it was done in bits and bobs it would be longer!!!
The LM Glouc to Worsc service might not go to Malvern and Hereford making them change twice!
"Avoid empty stock/ changing passengers at Oxford" - would running
HSTs▸ to at least Hanborough avoid this? Is this possible?
"Hanborough is prob out" - my mistake!