From 1800 to 1900 the territory of the United States expanded fourfold, and the population skyrocketed from about five million to seventy-five million plus. Two key innovations in technology helped this rapid development take place: steam and electricity. This easy-to-read guide traces the rail system's impact on shipping, travel, and the taming of the western frontier. Also covered are unprecedented advances in communication and other technology, such as new steel processes and improved farming tools. These changes not only ushered forth a new era of American progress but also formed the foundation of the modern world.