Into the South Draw and Tunnel 16

Tunnel 15 leads the main line into the South Draw, a valley between Eldorado Mountain, Crescent Mountain and Scar Top Mountain. In the South Draw, the main line makes a 180 degree horseshoe curve as part of the climb, including a penetration through Tunnel 16.

Satellite View of the South Draw Area.

Tunnel 16 is 698 feel long, and serves as a portion of the 180 degree curve. Upon exiting Tunnel 16, the main continues out of the South Draw, through the site of Old Tunnel 17. Old Tunnel 17 never was a tunnel. It started as a tunnel, but the rock proved to be too unstable and the tunnel collapsed during construction. The attempted tunnel was eventually removed, and the remains became a wide spot in the roadbed and a cut into the hillside of Scar Top Mountain. From there, the line continues around the ridge and back into South Boulder Canyon.

Looking across the South Draw towards the site of Old Tunnel 17. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

Approach to the East Portal of Tunnel 16. Photo from Rio Grande Secret Places, Volume 1 by R.C. Farewell.

Track Plan for the South Draw and Tunnel 16.

The layout plan for the South Draw and Tunnel 16 is a compromise of the prototype region versus the benchwork. While I was able to include part of the 180 degree curve, I had to reverse the curve in Tunnel 16. The result is less of a 180 degree horseshoe curve, and more of a dip into the South Draw gap and then an extended run up the draw. Tunnel 16 is represented with a 39.9" tunnel, and Old Tunnel 17 is also represented. Interestingly, its location falls near the track to Tunnel 10. At this point, the main line is about 35-3/8" (above the zero elevation) at Old Tunnel 17 and at 32" within Tunnel 10. Like the prototype, the main curves sharply around the end of the ridge coming off Scar Top Mountain and heads towards Tunnel 17.

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Cameron Turner