By September 1865, the Central Pacific Railroad had extended east from Sacramento as far as Camp 20, which was later renamed Colfax. The real assault on the Sierra Nevada began here. Colfax became a staging area for construction further uphill.
Beyond Colfax, construction began in August 1865, with much of the basic work to Dutch Flat completed by year's end. Major obstacles remained at Long Ravine, Secret Ravine, and Cape Horn. Trestles bridged the ravines, but Cape Horn loomed forebodingly. At Cape Horn, aided by a veritable army of Chinese laborers, railroad engineers carved a roadbed around the steep peninsula high above the American River canyon. Construction took a year. More than 300 Chinese workers fell to their deaths in the process.
Not until 1913 was the Cape double tracked, with the Cape Horn tunnel construction. Cape Horn represents one of the major railroad construction feats leading to completion of the First Transcontinental Railroad and the "Golden Spike" in Promontory, Utah on May 10, 1869.
Multiple historical writings on Cape Horn in Colfax, including the plaque that was dedicated in 1999, incorrectly note that the Chinese workers helped construct the railroad from woven chairs (called Bosun's chairs) lowered over the cliff side. In his 2001 paper The Central Pacific Railroad and the Legend of Cape Horn: Laborers in Baskets, Fact or Fiction, historian Edson T. Strobridge disputes the myth of the Chinese railroad workers laboring from wicker baskets from a steep, precarious cliff face. Strobridge painstakingly identifies written accounts perpetuating this myth, and disproves each one on. Strobridge notes that the first stories of the Bosun chairs over Cape Horn did not appear until 60 years after the construction of the railroad at Cape Horn, and describes the stories as "romantic but not true."
Passersby can view the Cape from a historical monument on Highway 174, about half a mile north of Colfax at the Red Frog Bar (formerly the Cape View Tavern). A hike down the Stevens Trail offers a richer, though more arduous exposure, to Cape Horn and the dramatic American River North Fork Canyon.
It is rumored that Chinese artifacts, dating back to 1865, are still found at the base of Cape Horn by amateur archaeologists and hikers.