The train hit a landslide near Stonehaven after heavy rain in an area where a drainage system had been incorrectly installed.
The 06:38 service to Glasgow had been unable to complete its journey due to the conditions and was returning to Aberdeen when the accident happened.
A recording of the driver showed he queried with a signaller if any reduced speed was needed to return north.
He was told everything was fine for normal speed.
The train struck debris from a landslide on the track, derailed, and collided with a bridge parapet.
During a court case in 2023, Network Rail admitted a number of maintenance and inspection failures before the crash.
It also admitted failing to warn the driver that part of the track was unsafe, or tell him to reduce his speed.
At the High Court in Aberdeen, Lord Matthews said no penalty could compensate for the loss suffered by the families of those who died and the people injured.
Law firm Digby Brown later said that a total of nearly £1m in civil actions against Network Rail had been settled.