On December 23, 1852, the first train on the first railroad west of the Mississippi River steamed proudly from St. Louis to Cheltenham—the immense distance of five miles. In that moment of exaltation, writes Robert Edgar Riegel, "flags waved, bands played, and orators prophesied the flowering of the West under the beneficent influence of the steam locomotive. For once the orators were right. An epoch was marked. Twenty-five years earlier the musical whistle of the locomotive was as yet unheard in the United States. Twenty-five years later steel tracks spanned the continent from New York to San Francisco."

In this account of the railroad conquest of the United States, the author is primarily concerned with the western phase of the story. He follows the Iron Horse west through Indian trouble, labor difficulties, civil war, and farmer disillusionment to the completion of the western railroad net. All aspects of the subject—financial, industrial, engineering, as well as the development of railroad regulation—are covered in this classic work.