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
West London Orbital including by Modern Railways magazine and the independent blogging community A number of routes have previously been examined for new orbital tube lines and improved connectivity across West and North London. It was considered that the most likely route of the previous proposal would be a north-south route running from Brent Cross to Surbiton, via Wembley Park, Ealing Broadway, Richmond and Kingston fully underground, connecting several London Underground and National Rail lines, including the forthcoming Crossrail 1 at Ealing Broadway. The proposal envisaged an underground driverless light rail train system similar to the Docklands Light Railway, and updated "to the