An investigation into the derailment of a log train in Palmerston North last year has found the speed of the train and the condition of the tracks were the likely cause.
The freight train with almost 40 loaded carriages derailed as it was leaving the city for Napier in April.
The Transport Accident Investigation Commission said the driver increased the train's speed after crossing over onto a parallel set of tracks, causing part of it to derail.
It is likely the conditions of the track and the speed of the train were contributing factors that caused the derailment, investigators said.
They recommended that KiwiRail improves the condition of tracks to reduce the likelihood of another derailment and ensure drivers have better control of trains.