London Underground Buses, Tramlink, London Overground, London River Services and Docklands Light Railway. Crossrail, due to open in 2019, is to be identified with a roundel. The 100th anniversary of the roundel was celebrated in 2008 by TfL commissioning 100 artists to produce works that celebrate the design. Seventy of the 270 London Underground stations use buildings that are on the Statutory List of Buildings of Special Architectural or Historic Interest, and five have entrances in listed buildings. The Metropolitan Railway's original seven stations were inspired by Italianate designs, with the platforms lit by daylight from above and by gas lights in
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