Redhill–Tonbridge line

The Redhill–Tonbridge line is a 19-mile-56-chain (31.7 km) railway line in South East England. It runs from the Brighton Main Line at Redhill in Surrey to the South Eastern Main Line at Tonbridge in Kent. There are five intermediate stations: Nutfield, Godstone, Edenbridge, Penshurst and Leigh. All passenger services run as all-stations shuttles between Redhill and Tonbridge, and are operated by Southern using Class 377 electric multiple units.

The route was opened by the South Eastern Railway in 1842 as part of the London to Dover main line. Since it was to be used primarily by express services, the line was engineered with few curves to allow high-speed running. At the time of construction, east Surrey and west Kent were sparsely populated and most of the intermediate stations are some distance from the settlements they purport to serve. In 1868, following the opening of the new main line via Orpington and Sevenoaks, which provided a shorter route from the capital, the Redhill–Tonbridge line was downgraded to secondary status. The line became part of the Southern Railway in 1923 and was incorporated into the Southern Region of British Railways in 1948.

Steam-hauled trains were withdrawn from the Redhill–Tonbridge line in 1965, when diesel multiple units were introduced. The new timetable consisted of an hourly service between Reading and Tonbridge via Redhill. From 1989, these trains were branded as "North Downs" services. In 1994, the line was electrified using the 750 V DC third-rail system, to provide a diversionary route for Channel Tunnel traffic. A new service between Gatwick Airport and Kent was introduced, operated by electric multiple units, which replaced the diesel service from Reading. In 1995, trains running to-and-from London via East Croydon were added.

At privatisation in 1996, responsibility for the Redhill–Tonbridge line was transferred to Connex South Eastern. The company was stripped of its franchise in 2003 and operations were passed to the publicly owned South Eastern Trains. On 1 April 2006, the line was taken over by Southeastern as part of the Integrated Kent Franchise, but in 2008, Southern assumed responsibility for all operations. Southern withdrew the Gatwick services that year and trains to-and-from London were discontinued in 2018, establishing the current shuttle service between Redhill and Tonbridge.