As well as ascending to Argentine Pass and Grays Peak, Wilcox purchased the Vidler Tunnel, a project begun in 1902 to expand an existing silver mine into a railroad tunnel under the pass. The line would have extended onward to Keystone, Colorado, and a junction with the Denver, South Park and Pacific Railroad. Work on the project stopped in 1911, by which time the tunnel was three-quarters completed. The tunnel project was revived as a highway tunnel in 1952, and the 1.4 mile tunnel was completed as a water diversion tunnel in 1969.