Skew Arch

Modern photo of Skew Arch
Skew Arch Bridge as preserved in the middle of 'old' route 22



This original structure is near the Lemon House and Engine House No. 6 Exhibit Shelter for the Allegheny Portage Railroad National Historic Site. You may walk down a trail or the mowed incline to access the Bridge. For visitors driving, it is located between the lanes of "old" Route 22 approximately one mile from the Summit Exit of "new" US Route 22. There are two parking spots on the traffic island in the middle of old US Route 22.


The skew arch is 60 feet 5 inches long on the south elevation, 54 feet 11 inches long on the north elevation, and 22 feet 2 inches high. Broken stone and stone sleepers taken from a section of the railroad were perched, fitted, and laid diagonally by hand without mortar.

The top of the bridge was not tilted but the arch's imposts were offset and constructed directly across from each other. Rectangular stones were cut into an L shape and were placed to reinforce the external corners of the pilasters and walls. No historic specifications or drawings have been found.


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.

On July 15, 1832, J. Fenlon, A. and J. Darlin, and R. Kininmouth won the contract to build " A Stone Bridge which will be require for the passage of the Turnpike road over the Rail Way on Section No. 36 of the Portage." The bridge was to be built according to specifications attached to and considered part of the contract.

The bridge design was changed in 1833 to accommodate a bend in the Huntington, Cambria and Indiana Turnpike road, hence the skewed arch. The construction journal duly noted on May 21, 1833, the expense of "Taking up & relaying masonry in consequence of alteration in place."

The Skew Arch Bridge was the only road bridge purposely built along the portage. Today the bridge is in fair condition. In 1979 the bridge was stabilized and repaired. Nearly the bridge's entire exterior has been repointed. Limited sealing was done and some of the facade was mortared.

For a PDF of the Skew Arch Bridge click on the highlighted link.

photograph of skew arch archeology work
2006 archeology work done at the Skew Arch Bridge.


Questions Remaining

Studies about and at the Skew Arch Bridge continue. Details about the Portage structures at the base of Incline 6 remain a mystery. Archeology work is done as interest and funding is available.

photo of the skew arch bridge tucked in its traffic island between lanes of 'old' 22
Older picture of Skew Arch Bridge tucked between the lanes of old route 22.



It is one thing to lose your job due to your poor performance, but what if your industry completely retools? What if your skills go beyond redundant to obsolete? What if your employer shuts down and there is no other employer who does the same thing? Can you learn new skills? Adapt your skills to a new industry? Are you able to bend around to fit old and new together in related areas? Can you accommodate your old competitor while keeping your own integrity?

Many of these questions are being asked of today’s workers. As technology grows and changes workers and resources must bend around new ideas, new challenges. This same competition is seen in the story of the Skew Arch Bridge at Allegheny Portage Railroad National Historic Site.

The Portage Railroad passed beneath the Skew Arch Bridge. The original hand hewn stone bridge was built at right angles to the railroad but that style created a difficulty for teamsters. A right angle turn was arduous for a wagon to negotiate; therefore to make the crossing compatible the bridge was turned, or skewed. This work was done by hand using skilled stonemasons and the careful planning of engineers.

The physical crossing of the railroad by the Huntingdon, Cambria, and Indiana Turnpike road was but one of the challenges to teamsters. A far larger challenge was the competition for contracts and resources with canals and railroads competing against wagons. Teamsters had hauled goods and raw materials from east to west across Pennsylvania for nearly a century. Using old Indian pathways, wagoneers slowly developed roadways to get materials from Philadelphia to Pittsburgh. Now a new system was being developed.

The Commonwealth of Pennsylvania decided in 1826 to create a canal system for the transport of goods east to west. This Mainline of Public Works was financed by the Commonwealth for the benefit of its citizens. Among its benefits was the reduction of travel time, Philadelphia to Pittsburgh, from 23 days to 5 days. The Allegheny Portage Railroad was a part of this Mainline system.

Teamster resistance to the Portage Railroad was fierce. As the railroad right-of- way was cleared the wagons used the newly cleared and graded surface as their thoroughfare. Even the interruptions of the railroad right-of-way by foundations for future engine houses were ignored by the teamsters in favor of a use as a new wagon road. It was not until the track was laid and the engine houses built that the route was reserved for portage traffic only.

In several places, including in the area of Incline No. 6 and the summit level, the turnpike ran parallel to the Portage Railroad. At one point, near the base of Incline No. 6, the turnpike intersected the railroad. To accommodate both methods of transportation the Skew Arch Bridge was built. This compromise lasted for the 20 years the portage railroad operated.

The Allegheny Portage Railroad was replaced by the Pennsylvania Railroad who used an entirely different route through and over the mountains. Just as the Portage Railroad substantially put the teamsters out of business so did the Pennsylvania Railroad make the Portage obsolete. Yet the Pennsylvania Railroad was not the last challenge to the Portage and its parts.

Modern transportation, including cars, buses, and trucks, competes with the railroads and may be leading them into obsolescence. The competition for contracts and resources between truckers, ironically called teamsters, and the Norfolk-Southern Railroad mirrors the struggle between wagon teamsters and the Portage Railroad. In some ways, the modern system of internal combustion engines is a challenge to other transportation systems, such as the railroads, as well as a challenge to our system of preservation of history.

The Skew Arch Bridge permitted the wagon road and the portage railroad to co-exist. The bridge originally built needed to bend as a compromise to assist the teamsters. The roadway of old US Route 22 bends to accommodate the Skew Arch Bridge. Engineers of this fairly modern highway had to change their plans to negate the necessity for removal of the Skew Arch Bridge. Today’s preferred method of transportation still can make room for the Allegheny Portage Railroad pieces to co-exist.

The continued existence of the Skew Arch Bridge is a testimony to compromise and competition. It tells the story of how two or more transportation systems can accommodate each other even as one may be slowly replacing the other. The story of the bridge is not only the story of the Allegheny Portage Railroad, but also the story of the changing views of efficiency and conservation.

Last updated: December 10, 2016

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