London Underground area, published by National Rail and Transport for London, includes suburban railway services. The tube map came second in a BBC and London Transport Museum poll asking for a favourite UK design icon of the 20th century and the underground's 150th anniversary was celebrated by a Google Doodle on the search engine. While the first use of a roundel in a London transport context was the trademark of the London General Omnibus Company registered in 1905, it was first used on the Underground in 1908 when the UERL placed a solid red circle behind station nameboards on platforms to highlight
Railway electrification system is provided by the running rails. On the London Underground, a top-contact third rail is beside the track, energized at DC, and a top-contact fourth rail is located centrally between the running rails at DC, which combine to provide a traction voltage of DC. The same system was used for Milan's earliest underground line, Milan Metro's line 1, whose more recent lines use an overhead catenary or a third rail. The key advantage of the four-rail system is that neither running rail carries any current. This scheme was introduced because of the problems of return currents, intended to be carried