The East Coast Main Line over which the 'Flying Scotsman' runs was built in the 19th century by many small railway companies, but mergers and acquisitions led to only three companies controlling the route; the North British Railway (NBR), the North Eastern Railway (NER) and the Great Northern Railway (GNR). In 1860 the three companies established the East Coast Joint Stock for through services using common vehicles, and it is from this agreement that the 'Flying Scotsman' came about. The 'Flying Scotsman' name has been maintained by the operators of the InterCity East Coast franchise since privatisation of British Rail; the former Great North Eastern Railway even subtitled itself The Route of the Flying Scotsman. The Flying Scotsman was operated by GNER from April 1996 until November 2007, then by National Express East Coast until November 2009, East Coast until April 2015, and Virgin Trains East Coast until June 2018. Since then, it has been operated by the government-owned London North Eastern Railway. On 23 May 2011 the Flying Scotsman brand was relaunched for a special daily fast service operated by East Coast departing Edinburgh at 05:40 and reaching London in exactly four hours, calling only at Newcastle, operated by an InterCity 225 'Mallard' set. 91 class locomotive 91101 and Driving Van Trailer 82205 were turned out in a special maroon livery for the launch of the service. East Coast said bringing back named trains would restore "a touch of glamour and romance". However, for the first time in its history, it ran in one direction only: there is no northbound equivalent service. This schedule is maintained today. Northbound, the fastest timetabled London to Edinburgh service now takes 4 hours 19 minutes. In October 2015, 91101 and 82205 were revinyled in a new Flying Scotsman livery. The Flying Scotsman is the only passenger service to run non-stop through Darlington and York. LNER's new "Azuma" units (Class 800s and Class 801s) took over the service on 1 August 2019. Since then, this one train is scheduled to run to London in 4 hours exactly.