considered separate: The Chessington line from Motspur Park to Chessington South The Epsom Downs line from Sutton to Epsom Downs The St Helier line from Sutton to Wimbledon The lines are electrified at 750 V DC third rail. Class 455 electrical multiple units are used, with semi-fast and stopping services to Horsham from London Victoria frequently operated by Class 377 Electrostars. Up to the early 1980s, express services to Littlehampton and Bognor Regis were routed along these lines and called at Sutton, Dorking, Horsham and stations to the south coast along the Arun Valley Line & West Coastway Line. The maximum speed is , with restrictions at Clapham Junction, Streatham Junction, Mitcham Junction, Raynes Park, West Croydon, Sutton and Epsom; at Dorking and the approach to London Victoria; and between Box Hill and Westhumble and Dorking, and between Dorking and Holmwood. Signalling between London Victoria and Ewell East (including the Epsom Downs Branch) is controlled by London Victoria (VC); between London Waterloo and Box Hill and Westhumble by Wimbledon (W); between Box Hill and Westhumble and Warnham by Dorking (CBK); and between West Croydon & Waddon and Warnham & Horsham by Three Bridges Signalling Centre (T). Platform lengths have been extended recently at most stations with twelve-car length platforms at Sutton, Horsham and Dorking and ten-car platforms at most other stations including Ashtead, Ewell East and Epsom. History of the route The lines used were the result of several schemes: 1847: West Croydon to Sutton and Epsom railway opened by the London, Brighton and South Coast Railway (LB&SCR) 1856: Epsom and Leatherhead Railway authorised. 1857: Wimbledon and Dorking Railway authorised under the auspices of the London and South Western Railway (L&SWR), reached no further than Epsom. This is why services are run by South West Trains. Autumn 1857: rival schemes to connect Shoreham Harbour with Horsham and Dorking. The London, Brighton and South Coast Railway (LBSCR) was eventually successful, on 1 August 1859. 1 February 1859: Epsom and Leatherhead Railway opened 4 March 1859: Wimbledon and Dorking Railway opened to Epsom by the L&SWR 1 July 1861: Shoreham – Horsham opened 17 July 1862: Horsham, Dorking and Leatherhead Railway (LBSCR sponsored) authorised. Opened in two sections: 11 March 1867: Leatherhead to Dorking 1 May 1867: Dorking to Horsham 22 May 1865 Epsom Downs Branch opened. 1 October 1868 The mainline route from London to Sutton via Hackbridge opened. 2 February