thames trains was a british train operator under franchise running a mixture of short and long distance trains around the thames valley. its services were centered around reading and ran in the area surrounded by oxford, gatwick airport, guildford, london, basingstoke, worcester, hereford and stratford-upon-avon. it was started when british rail was privatised and network southeast was broken up. in 2004 it was replaced by first great western link, which was merged with first great western and wessex trains after 2 years, forming a "greater western" franchise.