1885 Bookham branch and Guildford New Line (route via Cobham) open. Epsom and Leatherhead linked with Guildford by rail for the first time. 12 July 1925 Third rail electrified services begin between London Waterloo and Dorking North/Bookham and the Guildford New Line. July 1927 Leatherhead LSWR station closes – from 10th, all trains use LBSCR station, thanks to new spur. 3 March 1929 Third rail electrified services start between London Victoria and Epsom via Mitcham Jct and London Bridge and Epsom via Tulse Hill and Mitcham Jct. Epsom Town (LBSCR) station closed and services concentrated at new station on approximately the site of the former LSWR one. 1938 Dorking/Three Bridges to Horsham electrified. New signalling installed and new station built at Horsham. Colour light signalling through Dorking North (and new signalbox opened) from 15 May. Public third rail services start on 3 July. 1978 Portsmouth Harbour/Bognor Regis express services diverted via Gatwick Airport, and the lines downgraded including the removal of the passing loops at Cheam. A peak hour service continues, stopping at Sutton and Dorking. 1984 Dorking and Sutton lose their peak hour 12-coach fast trains to London and the south coast. 1997 Thameslink 2000 is announced with promises of a King's Lynn to Guildford service via London Bridge and West Croydon and an upgraded Wimbledon loop service to St Albans, with 12-coach trains. 2013 Platforms at intermediate stations along the route are extended to accommodate 10-coach suburban trains. Stations along the Epsom Downs branch have their platforms extended to accommodate 10-coach trains. Southern Trains introduces five car Class 377/6 on the route. May 2018 A new timetable comes into operation on the route affecting all services. The Epsom Downs line sees an uplift in off-peak services increasing to two trains per hour Monday to Saturday and a Sunday timetable is introduced. Also, improved connections between Epsom and West Croydon having 2 trains per hour, with the introduction of the all-day London Bridge to Epsom service. May 2019: is now served by 3 trains per hour in each direction as South Western Railway now stop here during off peak time (previously only during the peak). Accidents and incidents On 4 November 1942, two electric multiple units collided at due to a signalman's error. Two people were killed. On 6 November 1947, an electric multiple unit collided with another at due to errors by a fogsignalman. Four people were killed