The road began while it was still common for many travelers to walk alongside their wagons across the Great Plains to California and Oregon; a journey that could take six grueling months. It is no small wonder then, that America had railroad fever in the 19th century. The national imagination was propelled by the very real, albeit intimidating, prospect of building a railroad that joined east and west.
As it stood, only trails and wagon tracks crossed the wilderness in the mid-19th century. To bridge that wilderness with rails took six years and an army of 20,000 men, most of them immigrants from China and Europe. It took brute human effort, as the building was done entirely by hand. To this day, no one knows how many died in the effort, or what it really cost.
For many, a railroad was considered the key to westward expansion and the future of the country. A transcontinental route would greatly reduce the time it took to cross the continent, develop the nation's vast interior, encourage settlement, promote trade and fuel industry. Congress determined that a railroad linking the Atlantic and Pacific Oceans was also essential to national defense. The route east from California, though an awesome engineering prospect, had already been surveyed by Theodore Judah, of the Central Pacific. But by what route west? It was, for the moment, up to Congress to decide.
Southerners in Congress wanted a southern route, while northerners wanted a northern one. With the onset of the Civil War, the South seceeded, leaving the North to do as it pleased. Thus, a northern route (but still the most southernly one possible within the free states), following the Platte River Valley was chosen.
The Pacific Railroad Act of 1862 made construction of the transcontinental railroad possible. It designated tasks for two companies: the Central Pacific Railroad of California (CP) was to build eastward from Sacramento, and a new company called the Union Pacific (UP) was to build westward up the Platte River Valley from Omaha, Nebraska.