Chinese and Irish laborers for the Central Pacific Railroad working on the First transcontinental railroad lay ten miles of track in one day, a feat which has never been matched.

The Central Pacific Railroad (CPRR) was a rail company chartered by U.S. Congress in 1862 to build a railroad eastwards from Sacramento, California, to complete most of the western part of the "First transcontinental railroad" in North America. Incorporated in 1861, CPRR ceased independent operations in 1885 when the railroad was leased to the Southern Pacific Railroad Company. Its assets were formally merged into Southern Pacific in 1959.

America's first transcontinental railroad was a 1,911-mile (3,075 km) continuous railroad line built between 1863 and 1869 that connected the existing eastern U.S. rail network at Council Bluffs, Iowa, with the Pacific coast at the Oakland Long Wharf on San Francisco Bay. The rail line was built by three private companies over public lands provided by extensive U.S. land grants. Building was financed by both state and U.S. government subsidy bonds as well as by company-issued mortgage bonds. The Western Pacific Railroad Company built 132 miles (212 km) of track from the road's western terminus at Alameda/Oakland to Sacramento, California. The Central Pacific Railroad Company of California (CPRR) constructed 690 miles (1,110 km) east from Sacramento to Promontory Summit, Utah Territory. The Union Pacific Railroad (UPRR) built 1,085 miles (1,746 km) from the road's eastern terminus at the Missouri River settlements of Council Bluffs and Omaha, Nebraska, westward to Promontory Summit.