The Metropolitan District Railway, also known as the District Railway, was a passenger railway that served London from 1868 to 1933. Established in 1864 to complete an "inner circle" of lines connecting railway termini in London, the first part of the line opened using gas-lit wooden carriages hauled by steam locomotives. The Metropolitan Railway operated all services until the District Railway introduced its own trains in 1871. The railway was soon extended westwards through Earl's Court to Fulham, Richmond, Ealing and Hounslow. After completing the inner circle and reaching Whitechapel in 1884, it was extended to Upminster in Essex in 1902. To finance electrification at the beginning of the 20th century, American financier Charles Yerkes took it over and made it part of his Underground Electric Railways Company of London (UERL) group. Electric propulsion was introduced in 1905, and by the end of the year electric multiple units operated all of the services. On 1 July 1933, the District Railway and the other UERL railways were merged with the Metropolitan Railway and the capital's tramway and bus operators to form the London Passenger Transport Board. Today, former District Railway tracks and stations are used by the London Underground's District, Piccadilly and Circle lines. History Origins, 1863–1886 Inner Circle In 1863, the Metropolitan Railway (also known as the Met) opened the world's first underground railway. The line was built from Paddington beneath the New Road, connecting the main line railway termini at , and King's Cross. Then it followed Farringdon Road to a station at Farringdon Street in Smithfield, near the capital's financial heart in the City. The Met's early success prompted a flurry of applications to parliament in 1863 for new railways in London, many competing for similar routes. The House of Lords established a select committee that recommended an "inner circuit of railway that should abut, if not actually join, nearly all of the principal railway termini in the Metropolis". For the 1864 parliamentary session, railway schemes were presented that met the recommendation in varying ways and a joint committee composed of members of both Houses of Parliament reviewed the options. Proposals to extend west and then south from Paddington to South Kensington and east from Moorgate to Tower Hill were accepted and received Royal Assent on 29 July 1864. To complete the circuit, the committee encouraged the amalgamation of two schemes proposed to run via different routes between