Two major derailments in the South Island this week are unlikely to be connected, authorities say.
In the latest incident, five wagons of a freight train derailed after a passing loop at Waitati, 20km northeast of Dunedin, about 3.45am yesterday.
Three wagons toppled on to their sides, creating a potential
hazard for road traffic.
A crane was called in and it was hoped to have the track cleared by the end of the day.
The main trunk line south of Christchurch was blocked for more than a day after a train derailed on Monday afternoon at the Selwyn River Bridge near Dunsandel, causing 27 wagons to fall to the dry river bed.
Ontrack, the agency responsible for railway track maintenance and safety, is investigating both incidents.
Spokesman Kevin Ramshaw said there had been speculation that heat buckling of the tracks was responsible for Monday's derailment, but it could not yet be confirmed.
"Heat buckling would be unlikely to be a factor in the second incident," he said. "But an investigation is likely to take some time."
Derailments occurred randomly. "There is no particular pattern to them."
- NZPA
