Two train crew were injured when they jumped from a runaway train in Fife last month, accident investigators revealed today.
The incident happened after the DB Cargo train's brakes were damaged when it hit a fallen 1ft-thick tree branch and ran away for four miles.
The driver and a colleague suffered "minor injuries" when they jumped from the train as it started to roll backwards, the UK Government's Rail Accident Investigation Branch (RAIB) reported.
It has launched an investigation into the incident, which started during overnight leaf clearance north of Markinch around 4:25am on Tuesday, 17 October.
Some 60 trains during the morning rush hour were delayed or cancelled while the train was recovered and 10ft-long branch removed.
The RAIB said the driver had spotted the tree and applied the emergency brake.
However, the train hit the tree at 40mph, which damaged its underside and "caused the brakes to be irreversibly released".
It came to a halt after travelling uphill then started to roll backwards, when the train crew radioed an emergency and jumped clear.
The train finally stopped four miles to the south, near Thornton North junction, after travelling back and forth along a section of track several times because of the gradients.
David Ethell, head of safety and operations at DB Cargo UK, said: “At 4:41am on 17th October two men, one driver and one operative, had to eject themselves from an MPV (multi-purpose vehicle) near Markinch.
"They suffered minor injuries requiring medical attention.
"There were no other vehicles or individuals involved in the incident.
"An investigation is now underway in order to establish the full circumstances.”
A RAIB spokesperson said: "Prior to the collision, the train had been water jetting leaf debris from the rails.
"The driver saw the tree shortly before impact and applied the emergency brake.
"The train continued to slow following the collision, due to the uphill gradient.
"It came to a rest, but then started to roll backwards.
"Having made an emergency call on the train radio, the two train crew jumped from the train onto the trackside and suffered minor injuries.
"The train eventually came to a stop on a low point near to Thornton North Junction, after having oscillated up and down the adjacent track gradients several times."
The RAIB said its investigation would include the design of the train’s braking system, the actions of the train crew and the proximity of other trains on the route.
A Network Rail spokesperson said: “The safety of passengers and our workforce is of vital importance and we are already conducting our own internal review of the incident.
"We will work closely with the RAIB as it completes its inquiry.”