<P> The early tube lines, originally owned by several private companies, were brought together under the "UndergrounD" brand in the early 20th century and eventually merged along with the sub-surface lines and bus services in 1933 to form London Transport under the control of the London Passenger Transport Board (LPTB). The current operator, London Underground Limited (LUL), is a wholly owned subsidiary of Transport for London (TfL), the statutory corporation responsible for the transport network in Greater London . As of 2015, 92% of operational expenditure is covered by passenger fares . The Travelcard ticket was introduced in 1983 and Oyster, a contactless ticketing system, in 2003 . Contactless card payments were introduced in 2014, the first public transport system in the world to do so . </P> <P> The LPTB was a prominent patron of art and design, commissioning many new station buildings, posters and public artworks in a modernist style . The schematic Tube map, designed by Harry Beck in 1931, was voted a national design icon in 2006 and now includes other TfL transport systems such as the Docklands Light Railway, London Overground and TfL Rail . Other famous London Underground branding includes the roundel and Johnston typeface, created by Edward Johnston in 1916 . </P> <P> The idea of an underground railway linking the City of London with some of the railway termini in its urban centre was proposed in the 1830s, and the Metropolitan Railway was granted permission to build such a line in 1854 . To prepare construction, a short test tunnel was built in 1855 in Kibblesworth, a small town with geological properties similar to London . This test tunnel was used for two years in the development of the first underground train, and was later, in 1861, filled up . The world's first underground railway, it opened in January 1863 between Paddington and Farringdon using gas - lit wooden carriages hauled by steam locomotives . It was hailed as a success, carrying 38,000 passengers on the opening day, and borrowing trains from other railways to supplement the service . The Metropolitan District Railway (commonly known as the District Railway) opened in December 1868 from South Kensington to Westminster as part of a plan for an underground "inner circle" connecting London's main - line termini . The Metropolitan and District railways completed the Circle line in 1884, built using the cut and cover method . Both railways expanded, the District building five branches to the west reaching Ealing, Hounslow, Uxbridge, Richmond and Wimbledon and the Metropolitan eventually extended as far as Verney Junction in Buckinghamshire, more than 50 miles (80 km) from Baker Street and the centre of London . </P> <P> For the first deep - level tube line, the City and South London Railway, two 10 feet 2 inches (3.10 m) diameter circular tunnels were dug between King William Street (close to today's Monument station) and Stockwell, under the roads to avoid the need for agreement with owners of property on the surface . This opened in 1890 with electric locomotives that hauled carriages with small opaque windows, nicknamed padded 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 11 feet 8 inches (3.56 m) and 12 feet 2.5 inches (3.721 m), 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 16 - foot (4.9 m) diameter tunnels . </P>

What is the oldest line on the london underground
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