A cleanup is underway after a dramatic derailment of 11 freight cars near Pense, Saskatchewan.

It happened on the CN line Tuesday about eight kilometres northeast of the town.

No one was injured and there were no hazardous materials aboard the train, officials said.

The derailment left cars mangled and lying on their sides close to a dirt road and a water channel.

Heavy equipment was on the scene Wednesday morning as the cleanup continued.

The cause of the derailment isn't known.

It's the second big derailment in Saskatchewan this week.

On Sunday, seven passenger train cars derailed near the hamlet of Togo, close to the border with Manitoba, after the railbed was washed out from spring runoff.

No one was injured.