The construction and operation of the line was authorized by the Pacific Railroad Acts of 1862 and 1864 during the American Civil War. The Congress supported it with 30-year U.S. government bonds and extensive land grants of government-owned land. Completion of the railroad was the culmination of a decades-long movement to build such a line. It was one of the crowning achievements in the crossing of plains and high mountains westward by the Union Pacific and eastward by the Central Pacific. Opened for through traffic on May 10, 1869, with the driving of the "Last Spike" at Promontory Summit, Utah, the road established a mechanized transcontinental transportation network that revolutionized the population and economy of the American West.
The transcontinental railroad is considered one of the greatest American technological feats of the 19th century. It is considered to surpass the building of the Erie Canal in the 1820s and the crossing of the Isthmus of Panama by the Panama Railroad in 1855. It served as a vital link for trade, commerce and travel that joined the eastern and western halves of late 19th-century United