Officers from British Transport Police were called to the railway line close to Milton Keynes Central shortly before 9am on Tuesday following reports a person had been struck by a train.
Paramedics and officers attended and sadly the person was pronounced dead at the scene.
Work is now being done to identify them and inform their family.
A spokesman for British Transport Police said this week that officers were still making enquiries to establish how the person came to be on the tracks.
Trains were delayed due to the incident and the following investigation. Travellers were advised to check the situation before starting on their journeys.