London Underground L Stock London Underground L Stock London Underground L Stock was a clerestory-roofed rail stock built for the District line in 1932 and subsequently absorbed into the London Underground Q Stock, being redesignated Q31 Stock. The L Stock trains were built to provide additional rolling stock for the eastward extension of the District Line from Barking to Upminster. Two new electrified tracks were added parallel to the existing steam-operated LMS lines, including several new stations such as Upminster Bridge. Forty-five cars were built by the Union Construction Company, eight were driving motor cars and the rest were trailers. The eight motor cars,
History of the London Underground Harrow (later Uxbridge) and Hounslow. In 1933, the underground railways and all London area tram and bus operators were merged into the London Passenger Transport Board (LPTB). The outlying branches of the Metropolitan were closed; various upgrades were planned. The Bakerloo line's extension to take over the Metropolitan's Stanmore branch, and extensions of the Central and Northern lines, formed part of the 1930s New Works Programme. The outbreak of World War II in 1939 halted or interrupted some of this work, and many tube stations were used as air-raid shelters. The LPTB was nationalised in 1948, and the reconstruction of