In 1862 an Indiana state representative stated that the transcontinental railway "could never be constructed on terms applicable to ordinary roads . . . . It is to be constructed through almost impassible mountains, deep ravines, canyons, gorges, and over arid and sandy plains." Photographers like Alfred A. Hart documented the staggering constructions that, before the railroad, no one had imagined possible. Blasting through a naturally cemented part of the Sierra Nevada mountain range, crews of the Central Pacific Railroad built this immense corridor, sixty-three feet deep and eight hundred feet long.
Though Hart made this stereograph, its mount bears Carleton E. Watkins's name. Watkins was a San Francisco-based photographer who also chose the railroad as a primary subject. Because Hart's negatives belonged to the Central Pacific Railroad, they were subsequently printed by other company photographers who, like Watkins, failed to properly credit Hart.