This arrangement continues until Stoats Nest Junction just south of Purley; at this point the line splits into two double-track routes, often called Redhill line and Quarry line. The Redhill line is a continuation of the slow tracks and is used by stopping services via Redhill itself. It is also the only one of the two lines to have a junction with both the North Downs line and the Redhill-Tonbridge line. The Quarry line, meanwhile, bypasses Redhill by means of the Redhill Tunnel (passing under the line to Tonbridge) and is a continuation of the fast tracks. As such, it has no intermediate stops, although Coulsdon North station existed on the line until 1983.