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
Urban rail in the United Kingdom and Western England. Stations within London are served by two or four trains per hour. The London Overground (often shortened to "Overground") is operated by Arriva Rail London under a concession let by Transport for London, which owns the London Underground. The Overground includes the Watford Local, North & West London, East London & South and the Gospel Oak to Barking lines. It is the only National Rail service shown on the London Underground map. All stations are served at least every 20 minutes, with stations between and on the East London Line having 16 trains per hour in each