First Section of Transcontinental Railroad Opens

On July 20, 1865, the Central Pacific Railroad inaugurated service over its first completed stretch from Sacramento to Newcastle in the Sierra foothills. This segment overcame formidable engineering challenges including steep grades and river crossings using early 4-4-0 locomotives. Key figures included engineer Theodore Judah and the 'Big Four' investors. The opening symbolized the start of a project that would unite the nation after the Civil War, spurring economic growth and westward migration. Lasting impact included standardized track gauges and accelerated adoption of iron bridges across the American West.