Paulinskill Viaduct

The Paulinskill Viaduct, also known as the Hainesburg Viaduct, is a reinforced concrete railroad bridge that crosses the Paulins Kill in Knowlton Township, New Jersey. When completed in 1910, it was the largest reinforced concrete structure in the world.

The viaduct was built by the Delaware, Lackawanna and Western Railroad as part of the Lackawanna Cut-Off, a project that replaced an older route with a straighter and flatter route through the mountains of northwestern New Jersey. (A sister bridge of similar design but smaller dimension, the Delaware River Viaduct, carries the Lackawanna Cut-Off over the river, Interstate 80, and the New Jersey-Pennsylvania state line.) Designed by the DL&W's engineering staff under the supervision of chief engineer Lincoln Bush and built by the Philadelphia contracting firm of Reiter, Curtis & Hill, the bridge was considered a pioneering work that opened the door to the building of even larger concrete viaducts by the Lackawanna, most notably the Tunkhannock Viaduct in Pennsylvania in 1915.