BTP officers were called to Riddlesdown rail station in Purley on Friday, 22 March after a report that a woman and a child had been struck by a train.
The incident was reported to BTP at 8.29am and was also attended by Metropolitan Police officers.
Medics from the London Ambulance Service also attended, but a woman and a child were declared dead at the scene.
The station has been temporarily closed while officers and medics deal with the incident.
More top news
At a reception tonight at the Labour Party conference, our correspondent Emily Morgan believes she saw a glimpse of formidable Team Miliband
Performers faced the judges once again, this time with the added pressure of impressing a packed Wembley Arena.
Over 2,000 People's Climate March protests have taken place in 166 countries ahead of a major UN conference on climate change.