Keystone Viaduct

somerset | Meyersdale, PA Mile 29.8

The Nuts & Bolts: Keystone Viaduct

  • 910 feet long, Pennsylvania through truss bridge/deck-plated girder viaduct. Outfitted with I-beam supports.
  • Original Construction: completed in 1911
  • Rebuilt for GAP Use: September of 2003, raised 18” for CSX National Gateway Project in 2009.
  • Total Cost: $2,189,216.98
  • Engineer: Killam Associates/Hatch Mott McDonald/ DMJM Harris
  • Contractor: Brayman Construction
  • Project Manager: Brett Hollern

Southeast of the town of Meyersdale, Pennsylvania is a 910-foot-long amalgamation of a truss bridge and deck-plated girder viaduct dubbed the Keystone Viaduct.[1] This gently curved railway landmark, built in 1911, (along with its sister structure, the Salisbury Viaduct) was set to be demolished by order of the Pennsylvania Water Obstructions Act as part of negotiations between the Western Maryland Railway and the Western Pennsylvania Conservancy (WPC) beginning in June 1975.[2] Fortunately, this deal was overturned when the WPC declined to purchase the entire railroad right-of-way, acquiring only 26 miles through Ohiopyle State Park.[3]


In the early 1990s, when Somerset County sought to acquire the remainder of the Western Maryland right-of-way from CSX, they had similar liability concerns about the Keystone Viaduct than they did about the Salisbury Viaduct, and the county did not purchase the Keystone Viaduct with the rest of the Western Maryland Railway abandoned right-of-way.[4] In 1991, Somerset County Commissioner Dave Mankamyer was able to convince the other commissioners to eventually buy the 41 miles of right-of-way with the structures along the right-of-way purchased separately.[5]


In September 1995, as plans for the Keystone Viaduct were being discussed between the Somerset County Rails-to-Trails Association (SCRTA) and the Pennsylvania Department of Transportation (PennDOT), the Pennsylvania Public Utility Commission (PUC) held a hearing to decide if the Keystone Viaduct should be demolished to remove the support piers that obstructed Glade City Road.[6] Somerset County Trail Coordinator Brett Hollern, who oversaw the rehabilitation of the Keystone Viaduct and other precarious structures such as the Big Savage Tunnel, attended many PUC hearings between 1995 and the start of the project in 2002:

“There were seven particular crossings of the Western Maryland right-of-way that we’re in contention with the Pennsylvania Public Utilities Commission there. All those crossings had to come to resolution before we could expend any of the federal money that we had sitting there waiting to be spent. And, these were crossings that were mostly overhead crossings. The Keystone Viaduct was one of the crossings that was in order. And basically, what had to happen was all the parties that were at the table at this PUC case had to come to an agreement about how these crossings were going to be abolished whether it be the removal of bridges, the rehabilitation of bridges, and everybody sort of had their own separate stake in this…. PennDOT was a player, the Department of Conservation and Natural Resources, CSX because we crossed over the active CSX railroad [and Summit Township and the Pennsylvania Historical Museum Commission were also involved].”[7]


A compromise was made to adjust the piers at Glade City Road to allow more space for traffic flow, keeping the Keystone Viaduct from being dismantled. Because PennDOT was overseeing the project, modifications had to be made to the Keystone Viaduct in order for them to complete the project. Hollern had to make sure that the rehabilitation of the Keystone Viaduct met both PennDOT and PUC requirements:

“So, as part of that, PennDOT, the PUC – PennDOT said, “Well, you got to straighten our road if you’re going to do this bridge. You have to take out one of these piers or both of these piers.” And, the challenge was because the structure was curved, had a slight curvature to it, that the beams that were going to replace it had to mimic that curve. And then, I think we had to go with, like, COR-TEN Weathering Steel so it matched and didn’t look out of place and would weather and look like that’s how the structure always looked.”[8]


Rehabilitation of the Keystone Viaduct, after years of negotiation with the PUC, finally commenced on October 7, 2002.[9] However, as former Allegheny Trail Alliance president Linda McKenna Boxx recalls, having PennDOT take lead on the project meant that the trail builders lost a key argument about how the viaduct would be reconstructed:

“I think the spans were about 80 feet long each. And so, you created this 240-foot-wide span now, where before was, you know, whatever the distance between two offset piers were. And, with Ed Deaton and Dick Sprenkle from DCNR – we were arguing with PennDOT that we didn’t need to take out three spans, that one pier and two spans would do it, and argued with them for probably a good year until we finally gave up the argument and went with the two piers, three spans, because they were not going to budge.”[10]


To match the inevitable oxidization of the Keystone Viaduct, trailbuilders decided to think ahead of the curve by tinting the concrete decking a reddish-hue. The color was based on the ballast rock on the CSX tracks under the viaduct, with the iron oxide used to tint the concrete taken from a mine in Lowber, Pennsylvania. Nearly 2,000 tons of iron oxide were reclaimed in an effort to clean and recycle harmful iron oxidation in Sewickley Creek. The reclamation work was taken on by Iron Oxide Recovery Incorporated, a division under Hendin Environmental to cultivate and process the materials to Hoover Color Corporation in Virginia who further refines and purifies the oxide. Around 336 yards of tinted concrete was poured as decking in the summer of 2003, with the concrete still retaining its reddish-hue to this day, a humble reminder of Western Pennsylvania’s mining history and ever-present consequences on Pennsylvania’s surrounding natural environment.

The Keystone Viaduct was rehabilitated and finished in September 2003, but the work did not stop there. In 2009, six years after its official completion, the Viaduct had to be raised approximately 18 inches so that double-stacked CSX trains could pass beneath it.[11] CSX’s National Gateway Project, an initiative to improve the transport of freight and minimize the time it takes to deliver by double-stacking containers on every car, required the adjustment of infrastructure across the country–including the Keystone Viaduct and a tunnel through the Pinkerton Horn (near the GAP’s Pinkerton Tunnel).[12] The adjustments took a few months, and in addition to paying the construction costs CSX paid $25,000 to the GAP (which was used to fund the Garrett trail access).[13]

After years of uncertainty, the Keystone Viaduct was repurposed into a trail-worthy structure providing scenic views of the countryside just outside of Meyersdale. Out of the remains of the abandoned bones of a railroad came the opportunity to forge a new future for recreation and wellness in Somerset County.


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Author: Reed Hertzler, with edits by Jennifer Sopko