An investigation was launched after a passenger train sped into a 5mph zone at around 45mph.
The Glasgow Central to London Euston service failed to adhere to an emergency speed restriction put in place following the failure of an embankment.
The incident happened near Beattock in Dumfries and Galloway at around 12.25pm on December 20 last year.
The Rail Accident Investigation Branch (RAIB) said there were “no adverse consequences” as a result of the overspeed.
A preliminary examination was carried out into the circumstances surrounding the incident and a safety digest is to be published in the “next few weeks”.