Also known as the Hainesburg Viaduct, the Paulinskill Viaduct was built in 1909. It was (at the time of its construction) the largest viaduct of it’s kind in the world. The seven arched span is 1100 feet long and looms 115 feet above the roads, trees and river below. The Lackawanna Railroad was considered an engineering marvel as they built concrete overpasses rather then allowing for crossings, and built giant trestles rather then creating steep inclines to go over mountains. Read more here. It is part of the same line as the Byram Ice Tunnel and was the line that replaced the Manunka Chunk line, because it was shorter then Manunka Chunk and had fewer steep grades..
In the 1960’s the rail line was closed, and the rail beds torn up. It was neglected until the late 80’s when the State acquired it and the nearby land and added it to the state park. Of course going up top isn’t exactly encouraged mind you, safety and that kind of stuff. In May 2004, a man fell to his death and drowned in what is being labeled as an accident and possible suicide. Recently there are reports that there are now no trespassing signs posted around the PV.
If you go up this makeshift ladder you’d encounter some metal rungs which would lead you to a shaft which would lead thru a poop encrusted tunnel which would exit to the top of the structure. We didn’t use them because they looked rickety, and because getting severely injured 3 weeks before your wedding was not acceptable.
A turn by turn driving guide that lets you see all the various overpasses.
There are plans to resurrect the old rail line to carry commuters into NYC according to this article.