 The 1935–40 New Works Programme included the extension of the Central London (renamed the Central line in 1937) to West Ruislip in the west and to Epping and Ongar in the East.The stations and tunnels were enlarged to take 8-car trains of Standard Stock, the first 6-car trains running in 1938.The 3 rail electrical system was converted to the system's standard 4 rail system in 1940.