created: June 7, 2001
The Allegheny Portage Railroad linked the eastern and western sections of Pennsylvania's Main Line of Public Works, a system of canals, slack water, inclined planes, and railroad levels linking Philadelphia and Pittsburgh. Built during the late-1830's in response to New York State's Erie Canal, the "Main Line" was a hodge-podge of technologies that didn't mesh efficiently. The Allegheny Portage National Historic Site centers on the facilities at the top of Plane No. 6, where the portage railroad reached the summit of the eastern slope of the Allegheny Mountains. This is what the scene looked like in the 1840's. The hoist house is in the background. The stone building at right was Lemmon House, an inn and tavern serving travellers.
The Park Service has reconstructed a facsimilie of the hoist house over the excavated foundations and Lemmon House still stands. The reconstruction of the hoist house includes the hoist machinery, which can be viewed from elevated walk ways inside. With a little electronic manipulation, I've tried to show how the scene would appear today if an Impressionist painted it.
The interior of Lemmon House has been restored to its 1840's appearance. This is a view of the bar.
As you approach the hoist house along a short interpretive trail from the visitors center, this sign shows how the inclines worked. The cars approaching the hoist house in the picture are carrying sectional canal boats, which could be broken apart for carriage over the portage railroad. This design eliminated the need for passengers and cargo to be transferred twice between boats and rail cars. The cost savings in cargo shipment were significant. Relatively few of these sectional canal boats were built, however, and they came late in the life of the portage railroad. Throughout the "Main Line's" existence, passengers and cargo had to be transferred between canal boats and rail cars on both sides of the Portage Railroad. This expense and the high maintenance costs of the inclined plane hoist machinery and cables helped to make the Main Line a money losing operation. Compared to New York State's Erie Canal, the Main Line was a dismal failure.
This is the view of the hoist house from the overlook at the end of the trail from the visitors center. You can see how steep the slope of the plane was. The incline tracks were wooden stringers on wood cross ties. The stringers were capped with wrought iron straps.
This is a close-up view of strap iron-on-wood railroad track. The iron straps were short lengths of wrought iron spiked to the wooden stringers. Under heavy use, the ends of the iron straps tended to work loose and curl up, creating dangerous conditions for passengers in the wood-floored rail cars.
Long level stretches ran between the planes. Horses and, later, steam locomotives pulled rail cars on the levels. The track structure on the levels consisted of iron T-rail laid on stone slabs. This close-up view of T-rail tracks shows the "T"-shaped rolled iron rails resting in cast iron "chairs" pinned to stone "sleepers." This type of track construction was a technology adopted from English practices. But, although T-rail was more durable than strap iron, it was unsuitable for American conditions. Construction was labor-intensive, and in this pre-industrial period in American history when iron rails and castings were mostly imported from England, costs were high. On top of that, frost-heaves during the long Northeastern winters (which were much more severe than in England) caused the stone sleepers to shift and push the rails out of gauge. Eventually, American railroad engineers developed a hybrid track structure consisting of revised T-rail designs resting directly on wood cross ties.
Among the several living history programs staffed by Park Service employees and volunteers is a demonstration on quarrying and preparing stone slabs for T-rail track. Here a stone mason shows how holes for mounting cast iron chairs were marked and hand-drilled in a stone sleeper. The thousands of stone sleepers used in construction of the levels on the Allegheny Portage Railroad, including this one, were quarried directly from limestone out croppings that lined the route.
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