London Underground with smaller trains that run in two circular tunnels ("tubes") with a diameter about . These lines have the exclusive use of a pair of tracks, except for the Piccadilly line, which shares track with the District line between Acton Town and Hanger Lane Junction and with the Metropolitan line between Rayners Lane and Uxbridge; and the Bakerloo line, which shares track with London Overground services north of Queen's Park. Fifty-five per cent of the system runs on the surface. There are of cut-and-cover tunnel and of tube tunnel. Many of the central London underground stations on deep-level tube routes
London Underground large glass globes. Early District Railway stations were similar and on both railways the further from central London the station the simpler the construction. The City & South London Railway opened with red-brick buildings, designed by Thomas Phillips Figgis, topped with a lead-covered dome that contained the lift mechanism and weather vane (still visible at many stations e.g. Clapham Common. The Central London Railway appointed Harry Bell Measures as architect, who designed its pinkish-brown steel-framed buildings with larger entrances. In the first decade of the 20th century Leslie Green established a house style for the tube stations built by the