The Main Line of Public Works was a package of legislation passed by the Commonwealth of Pennsylvania in 1826 to establish a means of transporting freight between Philadelphia and Pittsburgh. It funded the construction of various long-proposed canal and road projects, mostly in southern Pennsylvania, that became a canal system and later added railroads. Built between 1826 and 1834, it established the Pennsylvania Canal System and the Allegheny Portage Railroad.

The Allegheny Portage Railroad was the first railroad constructed through the Allegheny Mountains in central Pennsylvania. It operated from 1834 to 1854 as the first transportation infrastructure through the gaps of the Allegheny that connected the midwest to the eastern seaboard across the barrier range of the Allegheny Front. Approximately 36 miles (58 km) long overall, both ends connected to the Pennsylvania Canal, and the system was primarily used as a portage railway, hauling river boats and barges over the divide between the Ohio and the Susquehanna Rivers. Today, the remains of the railroad are preserved within the Allegheny Portage Railroad National Historic Site operated by the National Park Service.