I am a historian in Beaver County, PA, where Penn Bridge Co. was located. My brother-in-law is an engineer currently doing structural work on this bridge, and he found the Penn Bridge Co. symbol on it. I didn't see Penn Bridge credited on your site, so I wanted to drop a line. Photos attached, and free to use.
I hauled the parts for the Kuzitrin bridge from Nome to the river in the summer of 1960. I did the survey for the abutments. They started putting up the bridge but a Crain collapsed with one of the truss sections and put the work on hold. I did the inspection on the batter pile driving. Hit blue ice and curled up the H-beams. Put Pointed shoes on the beams and drove them into the ice. Summer of 1961 we bathed and did our laundry by jumping into the 38 degree water and then swimming fast to shore. George Peterson
One of these massive and older Pennsylvania through trusses exists in Alaska. Look how tall the trusses are. These kinds of bridges are becoming extremely rare and every last one should be preserved.