I would hazzard a guess of a Florence & Cripple Creek bridge near Florence. Terrain looks right and the bridge looks like it has not seen a train in many, many years. Also, the idea that the F&CC made it to the end with wood bridges seems plausible.
Clear Creek line would have been gone for only 10 or 15 years (based on a guess of the age of the auto in the photo) and it was made into a paved highway even as the track was being removed. F&CC would have been gone the better part of 50 years and the bridge looks the part.
Jason Midyette