Emergency services are finding it difficult to access the scene where carriages overturned and piled on top of each other on a steep wooded slope.
Three people have died from the incident. The ScotRail train derailed on Wednesday morning in a narrow valley near Stonehaven, situated south of the city of Aberdeen.
After the accident occurred, dark smoke billowed from the accident site throughout most of the day.
Aerial footage showed one carriage detached from the rail tracks and lying on its side some distance down the slope. Another was completely overturned and had two carriages resting on it, one of which was also overturned.
Two air ambulances and about 30 emergency service vehicles could be seen in a field just above the site.
With rescue workers hampered by the steep terrain and dense woodland, it took many hours for casualty numbers to be confirmed.
"My deepest condolences are with the loved ones of those who lost their lives in this tragic incident," said Nicola Sturgeon, first minister of Scotland's semi-autonomous government.