Grain haulage company Qube Logistics has been forced to take 100 rail wagons out of service after one was found to have a fracture.
The Newcastle-bound train stopped at Gulgong last Wednesday where concerned staff noticed the wagon was sagging and had a large fracture.
Investigations later found fractures in the same place on other wagons in the fleet.
Qube Logistics told the ABC the wagons have been removed from service and structural tests were being carried out by independent engineers.
The company say they are working closely with the US manufacturer, American Railcar Industries, and the wagons will not be returned to service until they have passed necessary tests.
Image: The Northern Star