Southern Electric is the name given to the low voltage direct current top contact third rail electrified railway system in the south east of the United Kingdom. The Southern Electric Group is dedicated to both past history and current happenings on this system, the largest third rail electrified network in the world. Today's Southern Electric system extends across Kent, Sussex, Surrey, Berkshire, Hampshire, the Isle of Wight and Dorset. London terminals connected are Charing Cross, Cannon Street, Blackfriars, London Bridge, Waterloo and Victoria. 750V dc is today's standard, developed from the original LSWR concept. The Southern Railway adopted the LSWR system in preference to those devised by the LBSCR and SECR transforming the original third rail inner suburban network into a long distance and main line network. The pre-WW2 network reached Brighton, Hastings and Portsmouth on the south coast. The SR introduced standardisation of electrical equipment using components supplied by English Electric with the Southern Region of British Railways continuing as before. BR(S) extended the Southern Electric system to the Kent Coast in the early 1960s and reached Bournemouth later in the decade. Technical advances both in the electric traction field and in rolling stock construction into the 1980s saw a move away from the traditional camshaft controlled Mk I bodied trains. The 1990s brought re-privatisation and the eventual division of the Southern Electric amongst six new train operating companies with a single national infrastructure company.

• Southern Electric History and Infrastructure Part 1 - Origins
• Southern Electric History and Infrastructure Part 2 - The Southern Railway
• Southern Electric History and Infrastructure Part 3 - British Railways
• Southern Electric History and Infrastructure Part 4 - Re-privatisation