London Underground Railway Society

From their website: "The London Underground Railway Society (LURS) exists to study all aspects of Transport for London's metro railways, - past, present and future. Including LUL, London Overground, The Docklands Light Railway and Croydon Tramlink, as well as the relevant sections of London's Network Rail, and the now long disused Post Office Railway. Additionally, including some long forgotten and bizarre ones, in addition to the main London Underground system." http://www.lurs.org.uk/index.htm