Towns grew up as fast as workers could lay westward to Laramie, Rawlins, Rock Springs and Evanston. Elsewhere in the state, smaller lines were also built. Nine historic Wyoming depots are now museums - railroad and otherwise. Green River in the southwestern corner boasts the second pedestrian overpass across both the busy Union Pacific rail yard and the 1910 depot, now used for offices.

Interstate 80 parallels the Union Pacific route between Pine Bluffs and Evanston, providing ample opportunity to watch beef freight trains making their way across the prairie, the high desert and the mountains. While the Union Pacific is the dominant east/west railroad, BNSF is the main north/south line. Between them, they haul the more than 400 million tons of low-sulfur coal produced annually in Wyoming, the nation's number-one coal state, to the nation's hungry electricity-generating plants. Roughly a quarter of this output comes from ten huge mines in the Powder River Basin, south of Gillette. The UP and BNSF jointly own the rail line out of the coalfields, parallel to Highway 59 and are rapidly laying more tracks to keep up with the demand for coal. When the trains, each up to 1½ mile long, reach the North Platte River, the tracks split. Gillette, founded in 1891, was named after Edward Gillette, a railroad surveyor and engineer. If he were around today, he'd surely find work on the new tracks.