Why was the building of the railroads so important to mining and ranching?
Railroads offered the quickest way to transport freight in the 19th Century.
Prior to the Civil War, railroads east of the Mississippi River had shown how they could effectively and quickly move passengers and freight over great distances. Prior to the railroad, a trek of any distance greater than 50 miles became a multi-day ordeal. The American road system was in rough shape and the distance anyone could travel depended almost entirely on how far a team of horses could travel in a day.
The only effect long distance travel inland was on the barges which plied inland waterways. But by 1850, steam power had come into its own and tracks were being laid as fast as money could be raised and companies formed.
In 1862, the government authorized the building of the trans-continental railroad. The tracks started in Omaha in the east and Sacramento in the West, about 1900 miles in length. The federal government recognized that the railroad would be instrumental in opening up the western portions of the United States and its territories.