The cache is not at the posted coordinates, but you will need to go there to get the information needed to get the coords to the GZ. At the posted coordinates you'll find a metal plaque attached to the fence that discusses items found while doing the excavation for the Hudson-Bergen Light Rail Transit System. The plaque has a lot of interesting information if you care to read it, but to solve the puzzle, all you really need to know is what item was "among the items unearthed". Enter that word into the checker and you will be rewarded with the coords to the final.
You can validate your puzzle solution with certitude.