Emergency services were called to Smithy Bridge Station at around 6.30am following reports of a casualty on the tracks.
British Transport Police has said paramedics attended but sadly the person was pronounced dead.
The incident meant the line between Todmorden in Calderdale and Rochdale was blocked for three hours so that response teams could attend, leading to severe disruption for some train services between Leeds and Manchester.
A spokeswoman for British Transport Police said: “At 6.31am today, officers were called to Smithy Bridge station after reports of a casualty on the tracks. Paramedics also attended however a person was sadly pronounced dead at the scene. Officers are now working to identify the person and inform their family.
"This incident is not currently being treated as suspicious and a file will be prepared for the coroner.”