District line Railway (L&SWR), and branches reached Ealing Broadway, Hounslow and Wimbledon. As part of the project that completed the Circle line in October 1884, the District began to serve Whitechapel. Services began running to Upminster in 1902, after a link to the London, Tilbury & Southend Railway (LT&SR) had been built. At the start of the 20th century the District was seeing increased competition from the new electric underground tube lines and trams, and the use of steam locomotives underground led to unpopular smoke-filled stations and carriages. The American Charles Yerkes, who was later to form the Underground Electric Railways of
London Underground infrastructure Tube Programme, investigating replacing the trains for the Bakerloo and Piccadilly lines, is looking for trains with better energy conservation and regenerative braking. The Underground serves 270 stations. 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. The longest distance between two stations is between Chalfont & Latimer and Chesham on the Metropolitan line. The shortest distance between adjacent stations is the between Leicester Square and Covent Garden on the Piccadilly line. The station furthest