Officers were called to the line near Surbiton railway station at 11.39am this morning (9 February) following reports of a casualty on the tracks.
London Ambulance Service and London Fire Brigade also attended, however sadly the 30-year-old man from Hampshire was pronounced dead at the scene.
His family have been informed.
Officers are now working closely with colleagues at the Office of Rail and Road and the Rail Accident Investigation Branch to establish the full circumstances behind the man’s death.
Detective Chief Inspector Paul Langley said: “This is a tragic incident which has resulted in the very sad death of a railway worker. Our deepest condolences are with the man’s family who are being supported by specially trained officers.
“We are conducting full and thorough investigation into the incident and I would like to encourage anyone with information to please contact us as soon as possible. You can do this by texting 61016 or calling 0800 40 50 40 quoting reference 146 of 09/02/21.”