Union Pacific is investigating what caused more than a dozen train cars to derail in Hillsdale early Monday morning.

Spokesman Mike Jaixen says approximately 15 cars, some empty and some loaded, derailed around 2:15 a.m.

"Our crews are still working to clear the tracks at this time and that's something that should be done later this evening, certainly by late tonight," Jaixen said Monday afternoon. "After that, our crews will then inspect the track and make any necessary repairs."

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"They don't know what all the damage is going to be until all the cars are cleared," he added.

Jaixen says nobody was injured in the incident.

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