Third rail
The station was opened on 2 March 1868 by the South Eastern Railway (SER), when the SER opened its cut-off line between Chislehurst and Sevenoaks. Previously, trains between London and Tunbridge Wells had taken a circuitous route via Redhill. The line was widened and the station rebuilt in 1904, expanding to six platforms. Third rail electrification reached Orpington in 1925, and extended to Sevenoaks in 1935.