From National Rail:

Train services to, from and through Reading will be subject to considerable alteration between Tuesday 24th December 2013 and Wednesday 1st January 2014.

ALL ROUTES
Christmas Eve, Tuesday 24th December: services will run to a reduced timetable during the evening peak and all services will finish early – most services will have ceased running by 22.00.

Christmas Day, Wednesday 25th December and Boxing Day, Thursday 26th December: NO TRAIN SERVICES
On Boxing Day only, First RailAir will operate a limited coach service between Reading Station and Heathrow Airport, with some journeys extended to/from Gatwick Airport.

FIRST GREAT WESTERN SERVICES BETWEEN CHRISTMAS AND NEW YEAR
Between Friday 27th December and Wednesday 1st January inclusive there will be revised and reduced services on all First Great Western routes (suburban and main line) to and from London Paddington, due to Crossrail work. Some smaller London area stations will be closed, with Transport for London accepting rail tickets on alternative rail and bus routes. Revised timetables will also apply on Thames Valley branch lines.

Additional trains will operate between London Paddington and Reading during the early hours of New Year’s Day.

Between Christmas and New Year there will also be closures over the following lines, with replacement bus services operating (all dates inclusive):

– Reading-Basingstoke: Friday 27th December – Monday 30th December
Two bus services will run: one non-stop, the other serving Reading West, Mortimer and Bramley.

– Reading-Theale: Friday 27th December – Monday 30th December
A shuttle train service will run between Theale, Newbury and Bedwyn. Through trains between London and the West Country will be diverted via an alternative route between Reading and Westbury, or Reading and Taunton. Pewsey will be served by replacement bus service to/from Swindon.

– Redhill-Gatwick Airport: Friday 27th December – Sunday 29th December
Replacement buses will operate non-stop between Reigate and Gatwick Airport. Normal train times will apply between Reading and Redhill.

– Maidenhead-Marlow: Friday 27th December – Sunday 29th December, also Sunday 5th January
Between Monday 30th December and Friday 3rd January inclusive a revised train timetable will operate.

– Oxford-Banbury: Friday 27th and Saturday 28th December

The Night Riviera Sleeper service will not operate between Tuesday 24th and Tuesday 31st December. Trains will depart London and Penzance on the night of Monday 23rd December, and will resume with departures from London and Penzance on the night of Wednesday 1st January.

CROSS COUNTRY SERVICES BETWEEN CHRISTMAS AND NEW YEAR
These will be affected by the engineering work between Reading and Basingstoke from Friday 27th December to Monday 30th December; and between Banbury and Oxford on Friday 27th and Saturday 28th December. During this period Cross Country tickets will be accepted on First Great Western and South West Train services.

Friday 27th & Saturday 28th December: Trains will not operate between Banbury and Basingstoke. Replacement coaches will operate between Banbury and Winchester for longer-distance passengers. Replacement buses will also operate between Banbury and Oxford (connecting into train services between Oxford and Reading); and between Reading and Basingstoke.

Sunday 29th December: Trains will not operate between Reading and Basingstoke. Replacement coaches will operate between Oxford and Winchester for longer-distance passengers, as well as replacement buses between Reading and Basingstoke.

Monday 30th December: Trains will be diverted via an alternative route between Reading and Southampton Central, not calling at Basingstoke, Winchester or Southampton Airport Parkway. Journey times will be extended by up to 60 minutes. Replacement buses will operate between Reading and Basingstoke for connecting trains to and from Winchester and Southampton Parkway.

SOUTH WEST TRAINS (London-Reading route) BETWEEN CHRISTMAS AND NEW YEAR

A SATURDAY timetable will operate on Friday 27th, Saturday 28th, Monday 30th and Tuesday 31st December.

On Sunday 29th December trains will be diverted due to work in the Twickenham area, not calling at Twickenham or Richmond but instead at Hounslow and Kew Bridge. Replacement buses will operate between Hounslow, Twickenham and Richmond.

On Wednesday 1st January a SUNDAY timetable will operate.