Over many millennia, the Bighorn River cut a deep path through the spine of Sheep Mountain, also allowing Chicago, Burlington & Quincy to build a parallel path through the chasm in 1905-07. Today’s BNSF still uses this route to link the railroad between Casper, Wyoming, and Laurel, Montana, on the Casper Subdivision. On the morning of June 23, 2020, BNSF’s Cowley turn heads northbound along the Bighorn through the depth of Sheep Canyon as seen from high above on the canyon’s rim.