``We don't know what the cause was,'' said Steve Forsberg, a railroad spokesman. ``It's still under investigation.''
Forsberg said no one was injured in the derailment, which occurred shortly before 8 p.m. Sunday. The 34th through the 75th cars in the 110-car train left the tracks.
Tim Richmond, who works with the Wapello County Rural Fire Department, said he was taking out his trash when he heard the noise.
``I live right near there ... and thought 'That doesn't sound right,' so I hopped in my truck and headed down there,'' he said. ``You get a sense about these kind of things. It was just a little more than the usual braking noise.''
Cleanup began about 11 p.m. and continued through the night.
``There is some coal spilled on a county road close to the tracks,'' Forsberg said.
