Railway station in Travelcard Zone 3 opened 1849.
Has a disused platform. Unusually, the track in the bay remains in situ, although it is now heavily overgrown and otherwise obstructed. The area to the north (now a car-park) was formerly an area of railway sidings, where commuter trains were stabled when not in use.
The bay platform used to come into its own when a circus was taking place on Blackheath. Many of the animals would arrive in train vans.
The station for the start of the London Marathon.
The Wikipedia page is [1] and the TfL page [2] with buses at [3].