On Wednesday morning, distressing footage of plumes of smoke rising from an Aberdeenshire railway surfaced alongside reports of a train derailment.
As the day and rescue operation unfolded, it emerged that three people, including the train driver and conductor, had died.
Six more people were taken to hospital though their injuries are not thought to be serious.
The First Minister offered her “deepest condolences” to those involved in the crash and family members of the bereaved on Wednesday afternoon.
This is what we know so far about the incident at Carmont, west of Stonehaven.
What happened at Carmont?
At 09.43 British Transport Police were called to Carmont after the 06.38 train from Aberdeen to Glasgow derailed, with a landslide reportedly a contributory cause.
A crew member is said to have walked along the line for a mile to alert emergency services, while a member of the public also reported plumes of smoke coming from the railway.
In the lead up to the crash the region had experienced torrential rainfall and thunderstorms, with nearby Stonehaven receiving 79mm over 24 hours.
Prior to the crash, the driver reportedly asked permission to switch tracks.
It’s believed that he then reversed the train, switched tracks and continued south.
The train, consisting of two locomotives and four carriages, is then said to have hit a landslide.
Scottish Transport Secretary Michael Mattheson said that weather “had an impact” on the incident.
He said: "What we don't want to do at this particular point is to start to speculate about what actually caused it.
"What I think we can assess, though, is that weather has had an impact.”
Who are the victims?
Three people, including the train’s driver Brett McCullough, and its conductor Donald Dinnie, were killed in the crash when the train was hit by a landslide.
A passenger, who has not been named, was also killed. Six other people were taken to hospital.
Tributes have poured in for the known victims today.
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.”
Linda Spark, the cousin of Dinnie paid tribute to the conductor on Facebook, posting: "So sad that one of our relatives Donald Dinnie was a victim of the train accident in Aberdeen. Why is it always the good ones?"
When was the last fatal train crash in Scotland?
The Stonehaven derailment ends an unprecedented run of safety on Britain’s railways, and is the first fatal crash in Scotland since 1994.
Yesterday’s deaths were also the first fatalities on a train in Britain for 13 years, when a Glasgow-bound express derailed in Cumbria in 2007.
In 1994, two people died when a train derailed after vandals put concrete blocks on the line in Greenock.
The last previous deaths caused on the railway in Scotland happened at Newton on the edge of Glasgow in 1991.
Four people were killed and 22 were injured when two trains collided.
How have authorities reacted?
Network Rail is to carry out detailed inspections of high-risk trackside slopes with similar characteristics to the site of the Aberdeenshire crash.
The rail infrastructure body said it will use in-house engineers, specialist contractors and helicopter surveys for the work.
All “higher risk” sites where railway lines have been built through ground excavation and are similar to the location of Wednesday’s fatal accident will receive these “supplementary specialist inspections”.
Dozens of sites across Britain will be assessed.
Network Rail said it is working with meteorologists to strengthen the information it receives about flash flooding caused by extreme weather, so it can improve the way it deals with train operations.