Which railroad built westward from Omaha during construction of the first transcontinental railroad?

The Union Pacific Railroad built westward from Omaha during construction of the first transcontinental railroad.

The Union Pacific began at the Missouri River settlements around Omaha and Council Bluffs and laid track west toward Promontory Summit in Utah Territory. The Central Pacific Railroad built eastward from Sacramento, California, and the two lines met on May 10, 1869.

Congress supported the project through the Pacific Railway Act and land grants. Construction crossed plains, deserts, and mountain terrain, requiring large workforces, extensive supplies, bridges, tunnels, and telegraph coordination. Chinese laborers formed a major part of the Central Pacific workforce, while many Irish immigrants worked for the Union Pacific.

The meeting point was marked by the ceremonial driving of the “Last Spike” at Promontory Summit. The railroad connected the existing eastern rail network with the Pacific coast, although later extensions were needed to create the most direct routes to San Francisco.