A transcontinental railroad across the United States was once thought to be an impossible task. After all, rivers, mountains, and other types of difficult terrain stood in its way. But human ingenuity found a way and by 1869, the railroad was complete after the overcoming of many obstacles. This volume, beneficial to any elementary study of U.S. history, tells the fascinating story of this railroad's construction as well as explains its impact on the economy and western expansion. Fact boxes, sidebars, and historical images support the at-level text.