The Crystal Palace Line[1][2] is a railway line in London which runs from Balham Junction to Beckenham Junction. The engineer's reference for this line is BBJ.[3]
The line also provides a diversionary route for Thameslink services avoiding London Bridge – usually this is only in the peaks or during the night, but the Thameslink Programme engineering works have made it necessary for some Bedford to Brighton services to take this route throughout the day. These generally do not stop at any of the stations on the line.
The section from Beckenham Junction to Birkbeck is partly converted for Tramlink, with trams running from Beckenham to Croydon and Wimbledon.