London Underground Fourteen Underground stations are outside Greater London, of which five (Amersham, Chalfont & Latimer, Chesham, and Chorleywood on the Metropolitan line, and Epping on the Central line), are beyond the M25 London Orbital motorway. Of the 32 London boroughs, six (Bexley, Bromley, Croydon, Kingston, Lewisham and Sutton) are not served by the Underground network, while Hackney has Old Street and Manor House only just inside its boundaries. Lewisham used to be served by the East London line (stations at New Cross and New Cross Gate). The line and the stations were transferred to the London Overground network in 2010. London
London Underground cells". The Waterloo and City Railway opened in 1898, followed by the Central London Railway in 1900, known as the "twopenny tube". These two ran electric trains in circular tunnels having diameters between and , whereas the Great Northern and City Railway, which opened in 1904, was built to take main line trains from Finsbury Park to a Moorgate terminus in the City and had diameter tunnels. While steam locomotives were in use on the Underground there were contrasting health reports. There were many instances of passengers collapsing whilst travelling, due to heat and pollution, leading for calls to clean