HELLERTOWN, Pa. - The Walnut Street Bridge, also known as the Pony Bridge or Wagner’s Bridge, is constructed of cast iron and is 162 years old.
Roy “Chip” Wagner, a volunteer at the Hellertown Historical Society, has been submitting information about the structure, seeking national recognition of the Pennsylvania Historic and Museum Commission (PHMC).
The PHMC is supporting the span's nomination to the National Register of Historic Places.
The bridge’s original location was over Saucon Creek, about 200 yards from where it stands now. Chip Wagner’s family owned property on either side of the creek, hence one of its names.
“When I was a youngster, we probably all called it the Pony Bridge,” said Wagner. “I would say time, memories and changes of people in the area is why it has so many different names.”
The design and age of this bridge make it unique. Built in 1860 by Beckel Iron Foundry and Machine Shop in Bethlehem, it is constructed from cast and wrought iron. Wagner explained that the floor beams are especially unusual to see in a bridge now since the cast iron is quite brittle.
The next step in this process of historical recognition will be completed by the National Park Service. The Hellertown Historical Society should find out if the bridge will be certified for the National Register of Historic Places in February 2023.
The bridge remains standing today thanks to rehabilitation work done by Lehigh University graduate students in the 1990s. A small group of civil/structural engineers adopted the project when they passed the bridge on a class field trip in 1994.
The students found the bridge sitting alongside Saucon Creek. It had been removed from service in 1970 when the bridge became part of a high school bus route, as it could no longer hold the weight of large vehicles.
Perry Green, one of those students, reflected on the experience, especially the floors.
“You will not find floor beams like this anywhere in the world,” Green said.
As for the rest of the bridge, Green remembered the degree of detail.
“We had a sandblaster come in and sandblast all the pieces and everything, then got a zinc primer on it so it wouldn’t rust or corrode,” he said. “We cleaned up every one of the members, did a structural evaluation of what we needed to do to fix or to replace broken parts and pieces.”
The team disassembled and documented all pieces of the bridge before working with any parts. They replaced 72 wrought iron bars with steel bars and replaced three cast iron verticals. All other parts are original.
Atlas Lab on Lehigh’s Mountaintop Campus became a workspace for testing materials. Labor was volunteered and materials and machinery were donated.
Four years later the group of students finished the rehabilitation, leaving the bridge sitting at the mouth of a nature walk, not far from where they originally found it.
Wagner said historic details are lost when people move or pass away if no one works to write them down.
Placing this bridge on the National Register of Historic Places means it won’t be forgotten.
“It'll be there for everyone, you know, generations from now if someone wants to read about that bridge, there it'll be,” Wagner said.
The Grist Mill, just across the road from the Pony Bridge, will be his next endeavor of remembrance, Wagner said.
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