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,
West London Orbital most modern standards". The transit time from Brent Cross to Surbiton was quoted as 28 minutes, with a maximum train speed of 80 km/h. The promoters cited a number of reasons why they believed an underground scheme would be cost-effective at £1.75bn: with lower tunnelling costs as the tunnel diameter would be smaller than for a heavy rail scheme; there are no other rail tunnels to avoid (as in central London); and the subsoil strata are suitable for modern tunnel boring machines (TBMs). A number of other notable orbital rail schemes for London have been previously proposed: West London Orbital