A rush-hour train uncoupled and left half its passengers stranded because of a power surge, ScotRail has revealed.
The six-carriage split into two at Uphall in West Lothian, leaving the rear three coaches behind at the station.
Passengers trapped aboard were forced to activate the emergency door release to escape in what a union leader described as the “most serious railway incident in recent years”.
The UK Department for Transport’s rail accident investigation branch said it was still “reviewing” the incident on 26 November.
However, ScotRail has told The Scotsman its own investigation has found the cause to be “an electrical spike at the uncoupling point”.
It involved a class 334 electric train on the 5:20pm service from Edinburgh to Helensburgh.
A spokesman for the train operator said: “All train safety systems operated as normal, with the brakes on the trailing unit applying, and doors remaining closed.
“Passenger safety was not compromised.
“Both trains were removed from service for technical investigation.
“The investigation included the successful coupling of the units, testing of the coupling mechanisms on each train, and a review of the on-train data recorders.”
Train drivers’ union Aslef, which raised fears about the incident, said it had now been assured over safety.
Scottish organiser Kevin Lindsay said: “The extremely unusual event of the 334 units splitting has caused real concerns amongst ScotRail’s drivers.
“However, following the investigation by ScotRail’s fleet engineers and a full explanation of what has happened, we are content that these units are safe and it’s highly unlikely this incident will ever be repeated.”
But one train driver told The Scotsman: “We have not been given any reports or told of any outcome of investigations.
“The units uncoupled by themselves - that I have never heard of in my 30 years service.
“The incident happened on a platform and that alone was very lucky. If it was en route or stopped at a signal, who knows what could have happened?”
Office worker Murray Horn, 25, who was on the train, said: “We had to break the glass to escape the train as we weren’t sure if the train that was behind knew that we were there and might run into the back of us.