PATH Train

The things I learn from Wikipedia  Freaking scary:

PATH trains only use tunnels in Manhattan, Hoboken and downtown Jersey City. The tracks cross the Hudson River through century-old cast iron tubes that rest on the river bottom under a thin layer of silt. PATH’s routes from Grove Street in Jersey City west to Newark run in open cuts, at grade level, and on elevated track.

-“Port Authority Trans-Hudson.”  Wikipedia.  Accessed 30 March 2010.