Three Canadian Pacific railway workers were killed Monday in a derailment of a freight train in Canada's westernmost British Columbia province, the company said.

The westbound train went off the tracks east of the town of Field, in Yoho National Park, at about 1 am local time (0900 GMT).

David Karn, a spokesman for the British Columbia environment ministry, said 30 to 40 rail cars loaded with grain derailed, and the locomotive dropped into the Kicking Horse River.

Canadian Pacific said in a statement there was no threat to public safety and no dangerous goods were spilled in the crash.

The Canadian Transportation Safety Board was sending investigators to the scene.

There was another derailment in the same area last month, but without injuries.