Transcontinental Railroad: This was a 1,912-mile continuous railroad line constructed between 1863 and 1869 that connected the existing eastern U.S. rail network with the Pacific coast at San Francisco Bay.
Industrialization: This is a process by which an economy is transformed from primarily agricultural to one based on manufacturing goods. Individual manual labor is often replaced by mechanized mass production, and craftsmen are replaced by assembly lines. Railroads played a key role in this process in America.
Manifest Destiny: This was a widely held cultural belief in the 19th-century United States that American settlers were destined to expand across North America. The construction of railroads greatly facilitated this expansion.