A person was hit and killed by a train between Barnes and Clapham Junction on Tuesday.
South West Trains reported emergency services attending lines between the two stations shortly after 7pm.
British Transport Police (BTP) on Wednesday confirmed a woman in her 40s was killed.
Her family have been informed and police are not treating the incident as suspicious.
A spokesman for BTP said: "A 47-year-old woman has died after she was struck by a train at Wandsworth Town railway station yesterday evening [Tuesday].
"Officers were called to the station at 7.15pm and attended alongside paramedics from the London Ambulance Service.
"The woman’s family have been told. This incident is not being treated as suspicious and a file will be prepared for the coroner."
All lines in the area reopened by 9pm.
