London Overground (also known simply as the Overground) is a suburban rail network serving London and its environs. Established in 2007 to take over Silverlink Metro routes, it now serves a large part of Greater London as well as the home county of Hertfordshire, with 113 stations on nine different routes. The Overground forms part of the United Kingdom's National Rail network but it is under the concession control and branding of Transport for London. Operation has been contracted to Arriva Rail London since 2016. TfL assigned orange as a mode-specific colour for the Overground in branding and publicity including the roundel, on the Tube map, trains and stations. History Pre-1999 Rail services in Great Britain are mostly run under franchises operated by private train operating companies, marketed together as National Rail. The concept of developing a network of orbital services around London goes back to the independently produced Ringrail proposals in the early 1970s. Some of these were evaluated in the London Rail Study of 1974 (the Barren Report) and Barren suggested consideration of a North London Network of orbital services, based on a later suggestion by the Ringrail Group, which involved using many existing rail routes, rather than the new construction suggested in earlier drafts of the Ringrail Plan. The proposal from Barren was for several overlapping services mainly using the North London line, generally at 20-minute intervals. The suggested routes followed the original North London line service from Broad Street to Richmond, new services from Barking to Clapham Junction, and a third service from Ealing Broadway to North Woolwich. However, the Wilson government's continuing antipathy to the railways, along with British Rail's management's lack of interest in minor local train services, meant that few of these initiatives were carried forward. In 1979, the then Greater London Council (GLC) decided to sponsor an improved service from Camden Road, on the North London line, to North Woolwich, opening up a previously freight-only line between Dalston and Stratford and linking it to an improved Stratford – North Woolwich service. This was given the marketing name Crosstown Linkline, and operated with basic two-car diesel multiple units. The next initiative came from the GLC in 1984, when the government supported the Broadgate development that would entail the demolition of Broad Street station. The closure process was convoluted because of problems in making alternative arrangements for the North London line, and the remaining