Investigators are trying to determine the cause of a train derailment Thursday night in Wausau.
The last three cars of a Canadian National freight train jumped the tracks and one of them crashed into an office building in the rail yard. A cleaning worker inside was not hurt, but the crash damaged the walls and heating system.
Rail spokesman Patrick Waldron says the cause and circumstances of the crash remain under investigation.
Crews spent the morning Friday working to get the cars back on track and remove them.
Matt Lehman, WSAU