Emergency services were called after a body was found on the Wigan to Southport line near New Lane station in Burscough around 1.42pm on Sunday (September 26).
An air ambulance was also dispatched to the station but the girl, aged 15, was sadly pronounced dead at the scene.
Police say there are no suspicious circumstances involved in the tragedy.
On Sunday, British Transport Police (BTP) said officers were working to establish the full circumstances behind the death.
The investigation has now concluded and the force say details will be passed to HM coroner. The girl's family has been informed.
A BTP spokesman said: "Officers were called to New Lane station at 1.42pm on September 26 following reports of a casualty on the tracks.
"Paramedics also attended, however, sadly a 15-year-old girl was pronounced dead at the scene.
"Her family have been informed.
"The incident is not being treated as suspicious and a file will be prepared for the coroner."
Need to talk?
Whatever you're going through, the Samaritans can help you. They are available 24 hours a day, 365 days a year. You can call them for free on 116 123.