The first railroad to circumvent the Allegheny Mountains, the Allegheny Portage Railroad was the finishing piece of the Pennsylvania Mainline Canal. "The Portage," opened in 1834, marking the first time that there was one, direct route between Philadelphia and Pittsburgh. All things to all people, it served merchants, passengers, slaves in pursuit of freedom, and soldiers from the Mexican War.
The Allegheny Portage Railway National Historic Site, marks the final piece of the Pennsylvania Mainline Canal. Opened in 1834 "the portage" (an engineering marvel; rail line on a steep incline) completed the first direct connection for shipping and passengers between Philadelphia and Pittsburgh.