In 1863, the Metropolitan Railway began the world's first underground railway service between and Farringdon with wooden carriages and steam locomotives. The following year, a railway west from Paddington to Hammersmith was opened and this soon became operated and owned jointly by the Metropolitan and Great Western Railway companies. The line was then extended to the east, in stages, reaching the East London Railway in 1884. The line was electrified in 1906, and, in 1936, after the Metropolitan Railway had been absorbed by the London Passenger Transport Board, some Hammersmith & City line trains were extended over the former District Railway line to Barking. The Hammersmith & City route was shown on the Tube map as part of the Metropolitan line until 30 July 1990, when it was redesignated as a separate line.