An investigation has been launched after a train derailed on the Inverness to Perth Highland line, causing "significant damage" to the track.
The incident happened at about 22:15 on 29 October, south of Dunkeld and Birnam station.
The Rail Accident Investigation Branch said the railhead treatment train re-railed itself and no one was injured.
It said it had begun a preliminary investigation into the cause of the incident and will publish a report.
Railhead treatment trains use high-powered water jets to clear leaves from the line.