Broken springs behind derailing, says report

A freight train derailed in Waikato a year ago because springs on one of its wagon undercarriages were fractured, said a report released yesterday.

The southbound train left the tracks on a bend between Puketutu and Kopaki, southeast of Te Kuiti, on the main trunk line on March 24.

No one was injured.

The train's 27th wagon travelled off the rails for 750m before hitting a bar, derailing four other wagons and parting the train, the Transport Accident Investigation report said.

The wagon derailed because fractured springs on its bogie (wheeled undercarriage) could not stop the unit rolling excessively.

But the springs could not be identified in normal maintenance inspections, the report said. It recommended Toll NZ identify each bogie so its history could be tracked.

Toll said its workshops marked and recorded serial numbers on bogies but it would be years before all its wagons had been overhauled.

However, it said, "As bogies are changed based on condition (rather than kilometres travelled or time in service), we are unsure how [their] serialisation ... would help prevent a similar incident".

- NZPA