A ScotRail driver has failed a drugs test after his train was derailed by a suspected signalling fault, The Scotsman has learned.
The driver was suspended after the routine drugs and alcohol test following the incident, which closed the Dundee-Aberdeen line for two days.
The train derailed as it passed a set of points which connect tracks at Stonehaven station in Aberdeenshire.
It had no passengers on board, but the incident on 10 October blocked the line for 48 hours, causing major disruption. Dozens of trains were cancelled, with passengers switched to coaches.
Cross-Border LNER, CrossCountry and Caledonian Sleeper services as well as ScotRail trains were affected.
The incident is thought to have been caused by a signalling error or a fault with the points. A team from the UK Department for Transport’s Rail Accident Investigation Branch (RAIB) is still examining the incident and has yet to release any information about its cause.
There is nothing to suggest the derailment was caused by the actions of the driver or a fault with the trainScotRail
However, British Transport Police (BTP) said it was caused by a points failure and no “criminality” had been found.
ScotRail said the actions of the driver were not at fault.
It is believed the train was travelling at less than the speed limit and did not pass a red signal.
However, it is understood to be highly unusual for a driver to have tested positive for drugs.
Drivers are regularly subject to random checks, along with other ScotRail staff, in addition to tests in the wake of such incidents.
The drug traces identified in the test are still to be confirmed, it is understood.
This includes their origin, whether from recreational or prescription drugs.
Rail sources said staff who tested positive for drugs usually resigned immediately.
But the driver involved in this case is understood to have challenged the test result.
ScotRail declined to comment. A spokesperson said: “While investigations are still ongoing, there is nothing to suggest the derailment was caused by the actions of the driver or a fault with the train.”
A spokeswoman for BTP said: “We received a report of a train derailment near Stonehaven station at around 5:40pm on 10 October.
“Officers attended to understand the circumstances of the derailment and to assist passengers and railway staff.
“The cause of the derailment was found to be the result of a points failure.
“No evidence of criminality was identified and BTP are not investigating the matter any further.
“The Office or Rail and Road [which regulates track owner Network Rail] and RAIB were also notified.”
An RAIB spokesman said: “We’re still going through the evidence and are likely to make a decision on whether to investigate next week.”
Two years ago, The Scotsman revealed a ScotRail driver had been arrested for being drunk at Edinburgh Waverley station as he was about to drive a late-night train to Glasgow Queen Street.
Colin Chapman, 54, from Milngavie, was later given a 12-month supervision order and 200 hours of unpaid work after admitting being nearly nine times over the railway drink drive limit.
He was reported by staff for smelling of alcohol and found to have a blood alcohol reading of 174, compared to the legal limit of 20 for train drivers.
Sheriff Kenneth McGowan told Chapman at Edinburgh Sheriff Court his very serious offence “could have had devastating consequences for other people”.