There were multiple prior efforts to build a railroad over Rollins Pass in the 19th century and all attempts were met with impassable engineering challenges, financing issues, or both: GHS, Jefferson, & Boulder County Railroad and Wagon Road (A.N. Rogers' line) in 1867; U.P. in 1866; Kansas Pacific in 1869; Colorado Railroad (B. & M. subsidiary) in 1884—two tunnels located; Denver, Utah & Pacific in 1881 (construction started and tunnel located).: The remains of the latter tunneling attempt can still be seen on the northern slope of the rock wall at Yankee Doodle Lake and the detritus from the attempted excavation of the tunnel was placed at the northernmost part of the lake where pulverized granite tailings can be seen rising out of the water. These tailings were definitively from the 1880s tunneling efforts as they are not visible in the early stereoscopic images from the wagon road era of Yankee Doodle Lake; further, the attempted tunnel was not part of the later rail line that ultimately summited Rollins Pass.: