PARTS of the busy Cotswold Line commuter service will be shut during next year’s summer holidays for a long-awaited double-tracking scheme.

The detailed work plan has not yet been finalised, but train operator First Great Western is distributing leaflets before Christmas advising passengers of their expected timetable.

They are advising rail users alternative bus transport will be laid on, coinciding with the school holidays, between July 18 and August 30. But for Oxfordshire station commuters — including Charlbury through to Kingham — it could be as short as two weeks, according to the Cotswold Line Promotion Group.

Chairman, Derek Potter, said: “We have been waiting for this for 30 years, and it’s essential to improve services on what has been one of the worst performing lines.

“Obviously, we want the minimum of disruption and there may some slip back on the programme. But we have had meetings with FGW and Network Rail, and it’s possible that at the Charlbury and Hanborough end the blockade — or trains not running — will be down to just two weeks.”

Passengers to and from Oxford would board and get off trains at Hanborough, and continue the rest of their journeys by bus.

Network Rail was given final confirmation that funds would be available for the upgrading of the line at the end of October.

The Office of Rail Regulation has said it should cost £48m, but Network Rail has estimated a minimum cost of £51m.

The scheme involves the doubling of about five miles of track from just east of Charlbury to Ascott-under-Wychwood, and another 15 miles between Moreton-in-Marsh and Evesham.

The latter is expected to require a lengthier period of “blockade”, because of more extensive preliminary work in realigning the existing track, ballast, drainage and other work, because of a section of underground tunnel.

First Great Western spokesman, Adrian Booth, said they had decided to give out leaflets at all stations on the line, as well as on board trains, to keep commuters informed.

He said: “The dates for line closure are the best information we have at present, and we think that is better than nothing.

“It is the time of year when many people are thinking of booking their next summer holidays, so this could be useful information for them. On the parts of the track that are affected by closure, we will be providing shuttle bus travel, and, obviously, it will put extra time on journeys.”

Network Rail said it had options on the programme of work, which would depend on the exact funding it receives.

The double tracking should be completed between May and September 2010.