Tributes have been paid to train workers who died in a derailment near Stonehaven.
The driver and conductor, named locally as Brett McCullough and Donald Dinnie, were killed alongside a passenger.
Mr McCullough was a former gas engineer who decided to switch careers after servicing the boiler of a railway worker.
A union official said colleagues “thought the world” of the 45-year-old, who leaves wife Stephanie and three children, two girls and a boy.
Kevin Lindsay, Scotland organiser for the train drivers union Aslef, said: “The tragic accident at Stonehaven has affected everyone in the railway family.
“Brett thought the world of his family, and his colleagues thought the world of him.”
Six others were also injured when the 6.38am Aberdeen to Glasgow Queen Street service crashed on Wednesday morning amid heavy rain and flooding.
Speaking to BBC radio, ScotRail’s managing director Alex Hynes said: “Yesterday was a devastating day for everybody who works in the rail industry in Scotland.
“Our love and support is sent to the victims of this accident and their families, those that were injured in the accident and anybody who was touched by yesterday’s terrible tragedy.”
The Crown Office confirmed a joint investigation by Police Scotland, British Transport Police and the Office of Rail and Road was under way.
A separate probe will be carried out by the Rail Accident Investigation Branch (RAIB).
The Queen, Prime Minister Boris Johnson and First Minister Nicola Sturgeon paid tribute to those killed in the “tragic” incident.
Scottish Government transport secretary Michael Matheson visited Stonehaven on Thursday morning to meet members of the emergency services.
He said adverse weather was increasingly having an impact on routes and the RAIB probe would reveal whether mitigation works needed to be increased.
“I think it would be reasonable to presume, without unduly speculating, that weather had an impact in this particular incident,” Matheson said.
His UK Government equivalent Grant Shapps is due to arrive later.
Officials have pledged to find out what caused the train to derail.
British Transport Police (BTP) chief inspector Brian McAleese said an investigation would be directed by the Crown Office and Procurator Fiscal Service (COPFS).
He added BTP “will also be working closely with them along with the Rail Accident Investigation Branch and Office of Road and Rail to establish the full circumstances of how this train came to derail”.