The stretch of railway line where the derailment occurred has had problems with mudslides in the past.
In October 2018, a non-passenger service train derailed in the area. The crew were unhurt.
And in October 2002, the Aberdeen to Dundee line was closed due to a landslide at Carmont during torrential rain and gales.
The document said improvement work had been carried out at Carmont, specifically, “remediation of cutting slope following emergency, after mudslide due to flooding”.
Yesterday, ScotRail posted a message on Twitter shortly after 6.30am warning services across the country would be disrupted due to “extremely” heavy rain and flooding.
At Carmont, we’ve had reports of a landslip, which means services can’t operate between Dundee & Aberdeen. /2 pic.twitter.com/1E29tKHFhy
— Network Rail Scotland (@NetworkRailSCOT) August 12, 2020
A few hours later, Network Rail tweeted at 9.49am: “At Carmont, we’ve had reports of a landslip, which means services can’t operate between Dundee & Aberdeen.”
Police had said reports of the train derailment were first received at 9.40am.
It is believed the alarm was raised through the use of a signal box in the remote area of Carmont.
— Network Rail (@networkrail) August 12, 2020
ScotRail managing director Alex Hynes has said the rail operator is working with the emergency services on site as well as the relevant authorities to establish the cause of the incident.
Posting on social media, Mr Hynes said: “Our thoughts are with those who have been affected by this tragic event, particularly the families of those who have lost their lives.
“The railway in Scotland is a family and it’s one that is hurting today.”
The last major train accident in Scotland took place in 1991, where four people died in Newton.
In 1984, 13 people were killed in an accident near Polmont.