Buckled railway tracks in soaring temperatures are being blamed for the derailment of a goods train in National Park.

KiwiRail senior communications advisor Julie Buchanan says soaring temperatures, which peaked at 31 degrees Celsius at nearby Taumarunui on Tuesday, are behind the derailment blocking a level crossing in the Ruapehu district township.

The main trunk line was blocked by a derailed freight train at National Park. Photos: Stephanie Rangi/ Fairfax NZ

'It's definitely a factor,” says Julie. 'With this weather the tracks do buckle.”

'Most probably due to the hot weather heating up the tracks and causing possible buckling of the tracks which occurs when the tracks reach more than 40 degrees Celsius.”

Usually speed restrictions are put in place, but Julie didn't know whether that was the case.

The derailment happened around 4.30pm at the Fisher Road level crossing at the end of Carrol Street.

Police say no one was injured and the northbound freight train wasn't carrying any dangerous goods or gasses.

Kiwirail has been working to clear the site and say an investigating into the incident will be carried out.

-Chris Gardner, Aaron Leaman and Stephanie Rangi –Stuff.co.nz