TRAIN operators First Great Western and Chiltern Railways will operate special timetables tomorrow, due to the forecast of heavy snow overnight and in the morning.

The main changes planned for FGW services in Oxfordshire at present are the cancellation of a number of trains between London and Cardiff, which call at Didcot Parkway en route, and two morning peak services from Didcot to London.

FGW aims to operate normal services between Oxford, Reading and London and on the Cotswold Line between Oxford and Worcester but warns that its plans are subject to change at short notice, should weather conditions deteriorate. Passengers are advised to check if their services are running before setting out for stations.

The services from Didcot affected by cancellations are the 7.56am, 8.56am, 9.56am, 10.56am, 11.56am, 12.56pm, 1.56pm, 2.56pm and 3.56pm departures to Cardiff, via Swindon and Bristol Parkway.

In the opposite direction, trains from Cardiff to London which call at Didcot at 11.16am, 12.16pm, 1.16pm, 2.16pm, 3.16pm, 4.16pm, 5.16pm, 6.16pm and 7.16pm will not run.

In addition, the 5.53am from Cheltenham Spa to London, which forms the 7.19am service from Didcot to London, and the 6.30am from Bristol to London, which calls at Didcot at 7.28am, will not run.

In the south of the county, an hourly shuttle service will run on the Henley-Twyford branch line. Through trains between Henley and London will not run tomorrow.

An FGW spokesman said: "During the heavy snowfalls in February last year we operated the majority of our trains, and aim to do so again. We would like to apologise in advance for any inconvenience to your journeys."

Chiltern Railways is advising passengers to check its website for details of the revised timetable that will be in operation for its services from Banbury, Kings Sutton, Bicester North and Haddenham & Thame Parkway and for details of any extra short-notice alterations.

Chiltern's sister company Wrexham & Shropshire, which links Banbury with London, the West Midlands and North-east Wales, plans to operate a normal service, with four trains each way between London and Wrexham.

CrossCountry, which links Oxford and Banbury with the West Midlands and the South Coast, has yet to announce details of its plans for services tomorrow.

For the latest information, see the train operators' websites, or call National Rail Inquiries on 08457 484950.