The Allegheny Portage Railroad was the first railroad constructed through the Allegheny Mountains in central Pennsylvania, United States. (map) It was a series of 10 inclines, approximately long, and operated from 1834 to 1854. It connected two canal divisions of the Main Line of Public Works of the Pennsylvania Canal from Johnstown on the west to Hollidaysburg on the east, thus allowing continuous barge traffic between the Ohio and the Susquehanna rivers. Considered a technological marvel in its day, it played a critical role in opening the interior of the United States beyond the Appalachian Mountains to settlement and commerce. It included the first railroad tunnel in the United States, the Staple Bend Tunnel, and its inauguration was marked with great fanfare.
Today, the remains of the railroad are preserved within the Allegheny Portage Railroad National Historic Site operated by the National Park Service. The site was established on 1,296 acres (5.24 km²) in 1964 and is about west of Altoona.
The Lemon House, a tavern located alongside the railroad near Cresson that was a popular stop for railroad passengers, has been converted into a historical museum by the National Park Service. The park service also operates a visitor center with interpretive exhibits near the Lemon House.
The Staple Bend Tunnel is preserved in a separate unit of the historic site east of Johnstown.
In 1854 the portage railroad was rendered obsolete by construction of a locomotive railroad over the Alleghenies by the Pennsylvania Railroad, a private company. Despite this, construction on the New Portage Railroad, a $2.14 million realignment to bypass the inclines, continued, opening in 1856. On July 31, 1857, the Pennsylvania Railroad bought the portage railroad from the state, abandoning most and using the rest as local branches. In 1904 the part east of the Gallitzin Tunnels was reopened as a freight bypass line via the "Muleshoe Curve".