Driver distraction, speed led to derailment: report

A freight train derailment at Clinton in March last year was caused by a distracted driver and excessive speed, a Transport Accident Investigation Commission (TAIC) report has found.

On March 29, three wagons of a KiwiRail freight train derailed when exiting a crossing loop, as the train was travelling from Invercargill to Dunedin.

Two of the wagons overturned on to their sides.

The TAIC found the freight train had exceeded the maximum track speed when exiting the crossing loop, due to the driver becoming distracted.

The downhill gradient of the track allowed the train to accelerate to above the maximum permissible line speed.

“. . . The excessive speed combined with the track geometry at the point of derailment and the centre of gravity of the . . . coal wagons caused the wagon to oscillate from side to side.

“One or more wheels then lifted and climbed the rail, resulting in derailment.”

The wagon condition and loading were within KiwiRail’s maximum permissible limits.

A similar event occurred at the Clinton crossing loop in 2016.

At that time KiwiRail took safety actions after the incident, including speed monitoring and track repair.

However, a procedural control measure to ensure that loaded trains did not use the crossing loop was not adopted.

The report said as a result,

KiwiRail had taken a number of safety actions that address the issues raised in the report.

‘‘Therefore, no new recommendations have been made.”

A train driver could become distracted even when carrying out tasks specific to their role which could have unintended consequences, the TAIC said.

“To avoid repeat accidents and incidents it is important to learn from previous incidents.

“This requires a focus on implementing corrective action in accordance with the hierarchy of controls.

“However, when procedural control measures have been identified they should be implemented, checked and monitored properly to ensure the desired results are achieved.”