The Baltimore and Potomac Railroad (B&P) operated from Baltimore, Maryland, southwest to Washington, D.C., from 1872 to 1902. Owned and operated by the Pennsylvania Railroad, it was the second railroad company to connect the nation's capital to the Northeastern U.S., and competed with the older Baltimore and Ohio Railroad.

The Pennsylvania Railroad, legal name The Pennsylvania Railroad Company, also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia. It was named for the commonwealth in which it was established. At its peak in 1882, the Pennsylvania Railroad was the largest railroad, the largest transportation enterprise, and the largest corporation in the world.