Officers were called to the station at 7.30 a.m. after receiving reports of multiple bodies being found, the Independent reported.
London Ambulance Service paramedics said the three people were pronounced dead at the scene.
The deaths are being treated as "unexplained" and police said inquiries were being carried out to establish how they came on the tracks.
Detective Superintendent Gary Richardson from the BTP said: "My team are now working hard to understand what happened and how these three people came to lose their life on the railway."
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
