The Great Northern Railway was built to provide a direct link between London and Yorkshire. In addition to its passenger services the line handled the coal traffic from Nottingham, Lincolnshire and Yorkshire into the heart of London to feed the capital's insatiable appetite for the black stuff. The GNR's network gradually spread and through arrangements with other companies it ran trains into Manchester, from Doncaster to Leeds, and with further expansion into Derbyshire, Staffordshire and Cheshire. In 1923 the company became part of the LNER with the line from London to York forming the backbone of the East Coast Main Line to this day. During the nineteenth century and into the twentieth, the GNR produced a varied stable of locomotives under the leadership of several high-profile Locomotive Superintendents including Sturrock, Stirling, Ivatt and, in its latter years, Nigel Gresley. Their enduring legacy were the A1 and A3 Pacifics immortalised in the iconic streamliners of the LNER era.