London Underground

Rapid transit system in England

The London Underground (also known simply as the Underground or as the Tube) is a rapid transit system serving Greater London and parts of the adjacent home counties of Buckinghamshire, Essex, and Hertfordshire in England. Managed by Transport for London (TfL), the network spans 11 lines and 250 miles (400 km) of track, serving 272 stations. While the system's nickname originates from its deep-level circular tunnels, only 45% of the network is underground, with the majority of the outer surface tracks located north of the River Thames.

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