Lower Sydenham railway station is located on the boundary of London Borough of Bromley and the London Borough of Lewisham in south east London. The station serves the localities of Lower Sydenham and Southend. Served and managed by Southeastern, it is on the Hayes Line as part of its Metro routes. In Travelcard Zone 4 opened 1857.
More information on the Wikipedia page [1]. The Southeastern page is [2] and the TfL page [3].