An off-duty rail worker walked a mile to raise the alarm after surviving the train derailment which killed three people, it has emerged.
Driver Brett McCullough, conductor Donald Dinnie and a passenger Christopher Stuchbury died in the incident near Stonehaven on Wednesday.
A major investigation has begun into the derailment, believed to have been caused by a landslip after heavy rain.
Transport Secretary Michael Matheson said the survivor went to a signal box.
Mr Matheson told BBC Scotland’s The Nine there were a “number of actions” taken after the derailment.
He said: “There was a call made by someone who believed that an incident had taken place locally and they contacted Police Scotland.
“There was also an off-duty railway person on the train who, after it derailed, walked around a mile to the next signal box and advised them that an incident had occurred, which allowed Network Rail at its national control centre to close the line.
“During the course of that, Police Scotland obviously dispatched their staff and Network Rail dispatched some of the staff that they had working nearby to respond to the incident.”
He added of the investigation: “I want answers.”
The families of three men killed in a train derailment in Aberdeenshire earlier told of their devastation at their deaths.
It is thought that the 06:38 Aberdeen to Glasgow Queen Street service was derailed by a landslide after heavy rain in the area. It was returning to Aberdeen.
The alarm was raised at about 09:40 on Wednesday morning.
Six others who were on the train were taken to Aberdeen Royal Infirmary.
NHS Grampian said four of them had been discharged, while the other two patients were in a stable condition.
First Minister Nicola Sturgeon said the “hearts of a nation” were with those affected.
UK Transport Minister Grant Shapps has asked Network Rail to produce an interim report by 1 September.
He also said he spoke with PC Liam Mercer, the first officer on the scene, and commended him for his bravery.
Network Rail said it would carry out detailed inspections of high-risk trackside slopes with similar characteristics to the site of the Aberdeenshire crash.
Dozens of sites across Britain will be assessed using in-house engineers, specialist contractors and helicopter surveys.
Scotland’s Lord Advocate has asked Police Scotland, British Transport Police and the Office of Rail and Road, the independent regulator, to conduct a joint investigation into the accident.
It will be carried out under the direction of the Crown Office and Procurator Fiscal Service, and will run in parallel with the independent safety investigation being carried out by the Rail Accident Investigation Branch.