|Locale||East of England|
|Termini||London King's Cross
|Rolling stock||Class 313
Class 365 "Networker"
Class 387 "Electrostar"
|Number of tracks||Double track throughout|
|Track gauge||4 ft 8 1⁄2 in (1,435 mm) standard gauge|
|Route availability||RA 7-9|
|Electrification||25 kV AC OHLE|
|Operating speed||90 mph (140 km/h) maximum|
The Cambridge line runs from Cambridge junction on the East Coast Main Line to Shepreth Branch Junction on the West Anglia Main Line and forms part of the route between London King's Cross and East Anglia. The line is part of the Network Rail Strategic Route 5, SRS 05.05 and is classified as a London and South East Commuter line.
Plans for a line between Hitchin and Royston were placed before Parliament in 1846 by the Royston and Hitchin Railway company. The line was initially planned to be a single track spur from Hitchin, but during debate in the Lords it was recommended that the line be two track in the view of its possible later use as part of a route from Cambridge to Bedford although this was later superseded by the Varsity line via Sandy.  The line was opened in 1851 then extended to Cambridge although this was resisted by the company already operating a service from Liverpool Street via the West Anglia Main Line. The line was then leased by the Great Northern in 1850 and subsequently purchased in 1898 and through services run from London King's Cross to Cambridge.
As part of the Great Northern Route electrification by British Rail in the mid 1970s, the through service was severed by the need to change from the electrified service at Royston to a diesel train stopping at all stations to Cambridge. The extension of electrification through to Cambridge was completed in 1988 under Network SouthEast and the track improved to increase speed. Occasional services are run by 12 car trains  allowing them to stop only at Royston & Letchworth Garden City where the platform is long enough to accommodate them. The platform extension at Letchworth Garden City was completed in December 2011. The Down platforms at Shepreth and Foxton are being extended in May 2017 to allow 8 car trains to stop without blocking the level crossings.
The flat junction at Hitchin has always been an issue with conflicting train movements, but the Hitchin flyover to the north of the existing junction was opened in 2013 to carry north-bound services over the East Coast Main Line.
Services on the line are run by Great Northern as part of their Great Northern Route. A mix of Express, Fast and Stopping services are provided on the line as well as services via the Hertford loop to Moorgate which start and terminate from Letchworth Garden City.
The line is double track throughout. Traction current is supplied at 25 kV AC using overhead line equipment overseen by York Electrical Control Room, with Neutral Sections at Cambridge junction, Litlington and Shepreth Branch Junction. It has a loading gauge of W8 and a maximum line speed of 90 mph.
Route boundary and signalling
Just under a mile to the east of Royston station lies the boundary between the Network Rail London North Eastern Route and Anglia Route. All signals between King's Cross and this point are controlled by Kings Cross Power Signal Box, whilst those from here to Cambridge are controlled by Cambridge Signal Box. The signalling system for the whole Cambridge line is Track Circuit block, with all main signals being multiple-aspect colour light signals.
In order from southwest to north.
These are the passenger usage statistics on the National Rail network from the year beginning April 2002 to the year beginning April 2010. Comparing both years, Cambridge has increased by nearly 51%, Foxton by 57%, Shepreth by 99%, Meldreth by 41% although it has declined in recent years until this point, Royston increased by 28%, Ashwell and Morden by 30%, Baldock by 50%, Letchworth Garden City by 33% and Hitchin by 44%.
|Ashwell and Morden||89,061||98,481||96,452||108,013||104,417||116,908||112,350||115,720|
|Letchworth Garden City||1,091,229||1,144,661||1,186,565||1,309,067||1,364,936||1,445,886||1,366,714||1,447,418|
|The annual passenger usage is based on sales of tickets in stated financial years from Office of Rail Regulation statistics. The statistics are for passengers arriving and departing from each station and cover twelve month periods that start in April. Please note that methodology may vary year on year.|
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- "Platform extensions in South Cambridgeshire". Thameslink Programme. Retrieved 11 May 2017.
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- "Station Usage". Rail Statistics. Office of Rail Regulation. Retrieved 3 January 2013.
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