Sir Herbert Ashcombe Walker (1868 - 1949) became General Manager of the London and South Western Railway in 1912, where he instigated the programme of electrification (and for which he received his knighthood in 1915). He was then appointed General Manager of Southern Railway in 1923, where he then led the electrification programme for that company, and served as a Director until the end of its existence in 1947.

By 1929 the third-rail electrification of the London suburban network was completed, with the introduction of electric multiple units (EMUs) on principal suburban routes ensuring fast, efficient commuter services into London for the increasing volume of commuter traffic. The Southern Railway's commitment to electrification made the railway more innovative in its approach to handling traffic that its rivals, the intensive commuter system located within a small geographical area having made the Southern Railway a natural candidate for electric propulsion.

Most of the area immediately south of London was converted, together with the long-distance lines to Brighton, Eastbourne and Portsmouth - starting in 1931, this was one of the world's first modern mainline electrification schemes.

Tolworth Station, situated in the London Borough of Kingston upon Thames in South London, is a station on the Chessington branch 19 km (12.25 miles) south west of London Waterloo. The station is now part of the London suburban network of South West Trains. Like its sister stations on the branch, it's buildings and platforms were constructed from concrete in the style of Le Corbusier, so typical of the 1930s. It was opened in May 1938 as the original terminus of the branch. The station platforms lie below at street level on the Kingston Road. The original goods depot is still in use.