POSTED: 12/11/2009 01:00:00 AM MST
Investigators aren't yet sure what caused eight rail cars to derail Thursday morning, sending one crashing onto Colorado 72 with another tumbling close to a state highway department building and crews.
No one was injured in the 11:30 accident, but the road was closed for nearly six hours to allow transportation officials to look for clues at the site near Coal Creek Canyon.
"Everything is being looked at — the cars, the track, human factors," said Mark Davis, a spokesman for Union Pacific, which operated the train. "The crew is being interviewed about what they felt, and a separate group (of investigators) is looking at 'others,' (meaning) anything out of the ordinary."