The half past three train from Glasgow to Edinburgh was speeding through the station on the outskirts of the capital when the incident happened.
Services on the line were cut to every half an hour rather than the usual 15 minutes, causing travel chaos on the last working day before the bank holiday weekend.
A spokesman for the British Transport Police said: "At around 4.05pm a man was struck and killed by a train at Edinburgh Park train station.
"The train involved was the 15.30 Glasgow Queen Street and Edinburgh Waverley.
"Police are attending the scene and there appear to be no suspicious circumstances at this time."
A spokesman for ScotRail said: "Train services between Edinburgh and Glasgow Queen Street are being disrupted due to a person hit by a train."