Rollins Pass trestle (Devils Slide) from Panoramio, aiw0124.
The abandoned line over Rollins Pass was… originally built by the Denver, Northwestern and Pacific Railway, which was incorporated in 1902 to build a line west out of Denver to Salt Lake City, UT, on the opposite side of the Continental Divide. By this time, both Pueblo, CO (via the Denver, Rio Grande & Western) and Cheyenne, WY (via Union Pacific) had railroad lines heading west across the divide; it seemed logical that Denver should have one as well, and the DN&P was created for this purpose.
Construction on the line began in 1902, reaching the Continental Divide at Rollins Pass by 1903. By 1913, due to the difficulties of laying track in such mountainous terrain, the DN&P went into receivership and emerged as the Denver & Salt Lake Railroad, but it was for naught: construction on the line ultimately failed to reach Salt Lake City, only covering less than half the entire distance.
The climb over the top at Rollins Pass was fraught with numerous switchbacks, steep grades, and many instances of severe snow storms. These alone would seal the fate of the line over Rollins Pass, as the Moffat tunnel was built in 1928 to "replace" the tracks through the troublesome geography.
Today, the Moffat Tunnel is still in use by Union Pacific. The now-abandoned right-of-way over Rollins Pass branches from the UP line just east of the Moffat Tunnel's east portal, and then heads up to Rollins Pass via a series of switchbacks and tunnels. It then comes down the western side and meets back up with the active UP line at Winter Park. The entire abandoned route can be traced by following both Rollins Pass Road (on the eastern side) and Corona Pass Road (on the western side). (All text in italics is sourced from abandonedrails.com)
This GE image shows what appears to be an abandoned wye well up the Rollins Pass. This is only a small distance away from the trestle shown in the previous picture.
The “Needles Eye” tunnel has been closed for some years due to partial collapse of the tunnel roof. Panoramio photo from user Mike Bond.
Here in another GE shot you can see how the railroad twisted and turned in order to keep a manageable grade on the climb over the pass. We can see double horseshoe curves in what is now a road, although the route is not completely passable due to the present day poor condition of bridging or tunnelling.
Effectively this would be a kind of switchback although it doesn’t require reversal of the train as a true switchback would. It seems unlikely the railroad would have followed the hairpin bend in the road of today and instead it probably followed the big curve that is still visible at upper right. This is near the bottom of the pass and the active railroad that bypassed the route over the pass can be seen in the lower right corner of this image.
“Loop Trestle” as so described in Panoramio by user Elizabeth Haysmont. This is going down the other (western) side of the pass from that wye shown above. The road is called Corona Pass Road on the western side. Other Panoramio captions describe trestles in the same vicinity called “Rifle Sight Notch”. Most of these old trestles have been fenced off due to their dangerous condition. There was also a tunnel in the same area although I did not find a Panoramio photo of it.
Not sure but possibly the Rifle Sight Notch was part of a spiral with the trestle going over a tunnel. I still haven’t seen anything to conform where the tunnel was. The line continued down the hill until it met the approach to the Moffat Tunnel.