On 18 August 1981, half of the first and second sets derailed and rolled north of Waiouru when the northbound service was descending curves.
Passengers reported that the railcar had been travelling quickly over this section of the journey and the speed around curves just before the derailment had been concerning.
The subsequent enquiry found that many of the speed restriction boards for the curves in the area were missing or misleading; a full audit of speed restrictions across the entire rail network was one of the enquiry outcomes.
Four people were killed and another 16 injured.
The railcars were replaced by the "Blue Fern" on Wednesdays for three years until May 1984, to allow the two remaining railcar sets to be serviced while the damaged set was being repaired.

In 1989 and again in 1990 the Blue Fern train ran instead of railcars after Silver Fern railcar RM1 was involved in an accident.
On 18 August 1981, half of the first and second sets derailed and rolled north of Waiouru when the northbound service was descending curves. Passengers reported that the railcar had been travelling quickly over this section of the journey and the speed around curves just before the derailment had been concerning. The subsequent enquiry found that many of the speed restriction boards for the curves in the area were missing or misleading; a full audit of speed restrictions across the entire rail network was one of the enquiry outcomes. Four people were killed and another 16 injured. The railcars were replaced by the "Blue Fern" on Wednesdays for three years until May 1984, to allow the two remaining railcar sets to be serviced while the damaged set was being repaired.
In 1989 and again in 1990 the Blue Fern train ran instead of railcars after Silver Fern railcar RM1 was involved in an accident.
NZR RM class (Silver Fern)