Standing between two sets of rails, Carleton Watkins photographed a busy pair of tracks above Carson Valley, Nevada. His shadow and that of his mammoth-plate camera indicate his precarious position on the steep grade in the foreground. A single engineer stands near the empty track curving around a mountain on the left, having already observed the train that heads away from the trestle on the right. Beneath these tracks, another steam engine pulling lumber on multiple flatbed cars makes its way around a sharp curve. The wood carried by these trains was an essential material for building the railroad and for operating steam engines. Lumber served as ties beneath the iron rails, telegraph poles lining the route, and fuel for wood-burning steam engines.