The East Gloucestershire Railway Company was formed in 1861 to link Witney to Cheltenham, via Fairford. This original proposal had to be restricted to the 14-mile stretch between Witney and Fairford which was opened on 15th January 1863. In 1890 the East Gloucestershire Railway and Witney Railway (to Oxford) was absorbed into the Great Western Railway, the link to Cheltenham never being completed.
The initial timetable consisted of four passenger trains and two goods trains working each way on weekdays and by 1912 there were six daily passenger trains. At first there were seven intermediate stops between Oxford and Fairford; Kelmscott and Langford were added in December 1907, Cassington Halt in March 1936 and Carterton in October 1944. The branch became very important during the Second World War carrying munitions and troops with the proximity of seven major airfields; the railway actually crosses two of RAF Brize Norton’s taxiways.
After the war and throughout the 1950s there was a gradual decline in traffic on the branch back to four trains each weekday and which eventually culminated in the closure of the railway on 18th June 1962. The last public train running having run two days earlier. Today there is an industrial estate on the site of Fairford railway station now but there are still remains of the line marked by trackways and bridges. 
Loco 2236 at Fairford Station
The train was so slow building up steam to Lechlade that mushrooms could be gathered in this field on the other side of Fairford Bridge and the train reboarded.
Photographs courtesy of Jean Bennett
Bryworth Bridge near Fairford, 2006
Railway Bed at Fairford, 2006
Photographs Chris Hobson
Further reading:
Branch Line to Fairford by Vic Mitchell and Keith Smith in association with Richard Lingard. Middleton Press, 1988 ISBN 0 906520 52 5
http://www.disused-stations.org.uk
http://www.fairfordbranch.co.uk