The Allegheny Portage Railroad was constructed as a part of the Pennsylvania Mainline Canal System. It consisted of a series of 10 inclined planes and connecting levels that were used to transport railroad cars and canal boats over the Allegheny Mountains between Hollidaysburg and Johnstown- – a distance of 36.65 miles. The railroad was considered a major engineering accomplishment in its time and included the first railroad tunnel constructed in the United States.