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 Borough of Havering Romford, Gidea Park and Harold Wood. There is also a branch line from Romford to Upminster which is currently operated by London Overground. There are proposals for transport improvements in the south of the borough where the population is expected to rise. With the introduction of Crossrail there will be an increased service from Romford to both Central London and Reading. In March 2011, the main forms of transport that residents used to travel to work were: driving a car or van, 31.8% of all residents aged 16–74; train, 6.3%; underground, metro, light rail, tram, 6.3%; bus, minibus or coach,