
Three railroad tunnels were proposed in Colorado in 1920: Moffat Tunnel (under Rollins Pass) west of Denver, Cumbres Pass Tunnel near the New Mexico border, and Marshall Pass Tunnel near Salida.
The concept of a long tunnel under high mountain passes was proven back in 1906 with the opening of the 12-mile-long Simplon Railroad Tunnel between Switzerland and Italy, which goes right under high Alps peaks. This tunnel signaled to the railroad world that the fastest way to get trains across mountains is to go right through them.

photo: Railway Wonders of the World
Of the three proposed tunnels in Colorado, only the 6.2-mile-long Moffat Tunnel was ever built, but even that would not be completed for another 7 years, in 1927. As for the other two, which would have been on Denver & Rio Grande railroad lines, a diminishing demand for transportation in those remote areas meant that the cost of building and operating tunnels there could not be financially justified, and the bill to build them failed.
Today, you can take a step back in time by taking a train over beautiful Cumbres Pass at a leisurely 12 mph on the Cumbres & Toltec Scenic Railroad, which goes from Chama, New Mexico to Antonito, Colorado.

photo: https://cumbrestoltec.com/the-experience/scenic-highlights/
The former railroad line up and over Marshall Pass, which was built by Otto Mears in 1880, is now a popular OHV recreation road, and the Continental Divide Trail crosses at the summit of the pass.

photo: Denver & Rio Grande: The Early Years by Ferrell
For more information on the old Moffat Road railroad line and the dangers of high mountain passes, check out this previous blog post about two men who were killed in a boiler explosion on Rollins Pass.
Finally, Denver’s 32nd Mayor, Dewey Bailey, gets a shout out in today’s article, so here’s a picture of the Mayor, who may or may not have been involved in protecting the Blonger Brothers’ illegal bunco ring in Denver.

photo: Harry H. Buckwalter – Denver Library Digital Collections