Alfred A. Hart initially worked as a portrait painter before becoming a moving panorama painter in the 1850s. In the early 1860s he moved to Cleveland, opening an art gallery and store. He spent most of his time, however, traveling to California, and in 1865 he started to photograph the Central Pacific Railroad, working from 1866 to 1869 as their official photographer.

Unlike Russell, Hart did not produce large-format images, instead using just stereo-views. Eventually Central Pacific picked out 364 of these views to form a series documenting the entire line from Sacramento to Promontory. While Russell’s images celebrate the humans building the line, Hart’s focus was on the railroad (and its cuts, bridges, and tunnels) as a transformational agent, conquering the West through technology.