It runs from its western terminus at Tattenham Corner, near Epsom Downs Racecourse, to a junction with the Caterham line south of Purley.

[1][a] The buffer stops at Tattenham Corner are 23 miles 37 ch (37.8 km) down the line from London Charing Cross, when measured via Norwood Junction.

[5] Off-peak trains from Tattenham Corner typically reach Purley on the Brighton Main Line in around 23 minutes[2] and arrive at London Bridge in about an hour.

[7] The first proposals for a railway serving Tattenham Corner and Tadworth were drawn up in 1891 and a private bill was presented to Parliament in December 1891.

The driving force behind the scheme was a group of local landowners, including Cosmo Bonsor, later the chairman of the South Eastern Railway (SER).

c. cxlv) was passed, there were several objectors including the Epsom Grand Stand Association, who feared that their plans to extend the racecourse would be jeopardised by the construction of the line.

[3] On 2 November 1897, the section between Purley Junction and Kingswood opened as a single-track line with a passing loop at Chipstead, the only intermediate station.

[23] The final section of the line, between Tadworth and Tattenham Corner stations, opened on 4 June 1901, the day of the Epsom Derby.

[30] During the Second World War, casualties from the liberation of France were transported to a field hospital at Epsom Downs Racecourse via the line.

The company offered to install its overhead 6,700 V system, on the condition that it could lease the line from the South Eastern and Chatham Railway (SECR, the successor to the SER) and operate all services.

[34][d] Electric services started running between Purley and Tadworth on 25 March 1928 and the platforms at Reedham, Chipstead and Kingswood were lengthened to accommodate the new rolling stock.

[35] Initially the new trains used the same timings as their steam-hauled predecessors, but on 17 June 1928 a new, accelerated timetable was introduced, which also restored regular services to Tattenham Corner.

Taking the form of an island platform, linked by a concrete bridge to both sides of the line, it served a new area of semi-detached and terraced housing.

[46] The original wooden station building was damaged beyond economic repair on 1 December 1993, when a train crashed through the buffer stops.

[50] Under the Thameslink Programme, the Tattenham Corner line was to have been served by 8-car Class 700 trains to destinations north of the River Thames via London Blackfriars.

[2][51] However, in late 2017, these plans were altered and the line was dropped from the programme in favour of running Thameslink trains to Rainham, Kent.

[54] In 2022, the Sunday service on the route was reduced to a shuttle between Tattenham Corner and Purley, requiring passengers to change trains to continue their journeys to London.