Cambridge line in the context of West Anglia Main Line

The East Coast Main Line (ECML) is a 393-mile-long (632 km) electrified railway between its northern terminus at Edinburgh Waverley and southern terminus at London King's Cross. Peterborough, Doncaster, York, Darlington, Durham and Newcastle are on the line, which is a key transport artery on the eastern side of Great Britain running broadly parallel to the A1 road. The main line acts as a 'spine' for several diverging branches, serving destinations such as Cambridge, Leeds, Hull, Sunderland and Lincoln, all with direct services to London. In addition, a few ECML services extend beyond Edinburgh to serve other Scottish destinations, such as Stirling, Inverness, Dundee, or Aberdeen.

The line was built during the 1840s by three railway companies, the North British Railway, the North Eastern Railway, and the Great Northern Railway. In 1923, the Railways Act 1921 led to their amalgamation to form the London and North Eastern Railway (LNER) and the line became its primary route. The LNER competed with the London, Midland and Scottish Railway (LMS) for long-distance passenger traffic between London and Scotland. The LNER's chief mechanical engineer Nigel Gresley designed iconic Pacific steam locomotives including Flying Scotsman and Mallard, the latter of which achieved a world record speed for a steam locomotive, 126 mph (203 km/h) on the Grantham-to-Peterborough section on 3 July 1938.

Cambridge railway station is the principal station serving the city of Cambridge, in Cambridgeshire, England. Situated at the end of Station Road, it is 1 mile (1.6 km) south-east of the city centre. With over 10 million passengers passing through the station (2023–2024), it is both the busiest station in the East of England region and the thirteenth busiest outside of London.

The station serves as the northern terminus for both the West Anglia Main Line from London Liverpool Street, and of the Cambridge line from London Kings Cross. The station is also the southern terminus of three secondary routes: the Fen line to King's Lynn, the Breckland line to Norwich and the Ipswich–Ely line to Ipswich.