There are several major companies which build trains.
Some of them have bases in Britain, but new rolling stock is also imported.
Some trains are built in Britain.
There are two centres – Derby and Newton Aycliffe in County Durham.
The Derby works is owned by the Canadian firm of Bombardier, and Newton Aycliffe was opened in 2015 by the Japanese firm of Hitachi, mainly to build the new Intercity Express fleets which have been ordered by the Government for the Great Western and East Coast Main Lines.
There are several thousand companies in the railway supply chain, many of whom make components for the new trains which are assembled in Derby and County Durham.