BILLINGS, Mont. -

A BNSF Railway spokesman says the company is investigating the cause of a coal train derailment in which 13 cars came off the tracks in southeastern Montana.
    
BNSF spokesman Matt Jones said the loaded train originated at the Decker Mine in Bighorn County. It was en route to Superior, Wisconsin, when the cars derailed about 35 miles east of Billings at about 7:45 p.m. Thursday.
    
No one was injured, but some of the cars ended up on their sides.
    
Crews were expected to remain on the scene through Friday.
    
The line the coal train was using gets about 20 trains per day. It was expected to re-open early Saturday morning.