Portal:Trains/Selected article/Week 20, 2014

The District line is a London Underground service that crosses Greater London from east to west. From Upminster, the eastern terminus, the line runs through Central London to Earl's Court before dividing into three western branches, to Ealing Broadway, Wimbledon and Richmond. A branch also runs north from Earl's Court to Edgware Road via Paddington. Coloured green on the tube map, the line serves 60 stations in 64 km, and with bridges across the Thames on the Wimbledon and Richmond branches is the only London Underground line to cross the river in this way. Unlike London's deep-level tube railways, the railway tunnels are just below the surface, and the trains are of a similar size to those on British main lines. The original Metropolitan District Railway (as it was then called) 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. Services were operated at first using wooden carriages hauled by steam locomotives. Electrification was financed by the American Charles Yerkes, and electric services began in 1905. In 1933 the railway was absorbed by the London Passenger Transport Board. In the first half of the 1930s the Piccadilly line took over the Uxbridge and Hounslow branches, although a peak-hour District line service ran on the Hounslow branch until 1964. The trains carried guards until one-person operation was introduced in 1985. The District line is the busiest of the sub-surface lines as well as the fifth busiest line overall on the London Underground with over 208 million passengers in the year 2011/12.