A buddy of mine worked for RJ Corman, he was sent to Colorado (Arvada area?) on storm cleanup-repair for a couple weeks. He sent me a shot of one of the projects they were working on back in September. Don't know where exactly this was, he said it was on BNSF. Front Range Sub, maybe? Apparently this was a fill area, used to be a bridge here at one time but it was filled in. You can see how small the stream is at the bottom of the picture. Really puts the magnitutde of those storms in perspective, how that little stream washed all of that out.
It can easily happen. A plugged culvert, or debris piled up against a trestle builds up an enormous side pressure, with the weight of all that accumulated water. Fills are not designed to resist this problem.
http://www.denverpost.com/portlet/article/html/imageDisplay.jsp?contentItemRelationshipId=5419847 Coal Creek, I think, is the washout. Full story with photos here: http://www.denverpost.com/breakingn...freight-trains-flood-zones-likely-out-through