Gary Wells, 36, was struck by the train near Fort William station on Tuesday. Emergency services were called to the incident but he died at the scene.
Diane MacDonald, who reportedly separated from Mr Wells recently, was driving the ScotRail train between Mallaig and Queen Street, Glasgow. She was informed of the death later.
A statement issued on behalf of Miss MacDonald by her employer said: "The circumstances are extremely upsetting for everyone involved. We would ask the media to please respect our privacy while we come to terms with what has happened."
British Transport Police said the man's family had been informed, and the death was not being treated as suspicious.
A report will be sent to the procurator-fiscal.