The Kensington and Richmond line was a railway in West London, England. It was built by the London and South Western Railway, which already had a main line to Richmond from London. The Kensington line was chiefly a defensive measure to limit the incursion of rival railways into LSWR territory. It ran from Kensington on the West London Railway, by way of Hammersmith, Turnham Green, Gunnersbury and Kew; it opened in 1869. It had a separate station at Richmond, in keeping with the LSWR intention of preventing competitors from easily obtaining running powers to go further into the LSWR area.
Nevertheless, several competing companies ran passenger train services into Richmond over part of the line, and the Midland Railway developed an important route for the supply of house coal to the developing suburbs served. In 1877 the Metropolitan District Railway connected to the Kensington line at Hammersmith, and ran an increasingly intensive passenger service to Richmond. From 1879 the District operated to Ealing, and soon the volume of its train service swamped the capacity of the shared route section, from near Hammersmith to Turnham Green. When the District Railway electrified its train services in 1905, it was obvious that line capacity was overwhelmed, and the line was quadrupled from 1911, the District Railway being allocated a dedicated double track.
The LSWR had almost exclusive use of the other double track, but its own service, now seen by the public as inferior, was declining steeply, and in 1916 it was withdrawn completely. The LSWR pair of tracks remained dormant for ten years, until in 1926 the District Railway implemented a widening scheme. By taking the ground formerly occupied by the LSWR, the District Railway, now part of the Underground system, was able to quadruple its own tracks. This was operational from 1932, with the Piccadilly Line operating fast services on the centre two tracks and the District Line working stopping trains on the outer pair. This applied between Hammersmith (at the former Studland Road Junction) and Turnham Green. From Studland Road Junction to Kensington was now derelict and the land was sold. From Turnham Green to Richmond, the line continued, but was now used by the District Line trains and the North London Line trains from Broad Street, later from North Woolwich.