Circle line (London Underground) and the C Stock trains have recently been replaced by new seven-car S Stock trains, in a programme completed in 2015. In 1863 the Metropolitan Railway, the world's first underground railway, opened in London between Paddington and Farringdon, connecting the Great Western Railway's relatively remote terminus at Paddington with Euston and King's Cross stations and the City, London's financial heart. In the same year a select committee report recommended an 'inner circle' of railway lines connecting the London termini that had been built or under construction. In the next year the Metropolitan District Railway (commonly known as the District Railway)
London Underground infrastructure London Underground infrastructure The infrastructure of the London Underground includes 11 lines, with 270 stations. There are two types of line on the London Underground: services that run on the sub-surface network that is just below the surface and use larger trains, and the deep-tube lines, that are for the most part self-contained and use smaller trains. Most of the lines emerge on to the surface outside the central area. The oldest trains running on the Underground were introduced in 1972. The Underground is electrified using a four-rail system, the DC traction supply being independent of the running rails. Planned