Construction of the northern tube under the Hudson River in 1905
Led by Chief Engineer Charles M. Jacobs, the tunnel design team began work in 1902.
After plans were complete in 1904, the first task was digging two shafts, one just east of 11th Ave in Manhattan and a larger one a few hundred yards west of the river. The Weehawken Shaft was completed in September 1904 as a concrete-walled rectangular pit, 56 by 116 ft at the bottom and 76 ft deep.
When the shafts were complete, O'Rourke Engineering Construction Company began work on the tunnels proper. The project was divided into three parts, each managed by a resident engineer: The "Terminal Station" in Manhattan; the "River Tunnels", east from the Weehawken Shaft and under the Hudson River; and the Bergen Hill tunnels, west from the Weehawken Shaft to the tunnel portals on the west side of the Palisades.:45 (At the time, "North River Tunnels" referred to the tunnels east of the Weehawken Shaft; in later years the term has come to include the Bergen Hill tunnels as well.) The tunnels were built with drilling and blasting techniques and tunnelling shields, digging west from Manhattan, east and west from Weehawken, and east from the Bergen portals. The two ends of the northern tube under the river met in September 1906; at that time it was the longest underwater tunnel in the world.
Except for a curve west of the west end of Pier 72 that totals just under a degree, the two tracks are straight (in plan view); they are 37 feet (11 m) apart from west of 11th Avenue to the Bergen Hill portals. The third rail now ends just west of the Bergen Hill portals.
Since 2003 the tunnels have been operating near capacity during peak hours. Trains ordinarily travel west (to New Jersey) through the north tube and east (to Manhattan) through the south. During the morning rush about 24 trains are scheduled through the south tube in the busiest hour, and the same through the north tube in the afternoon.
In May 2014 Amtrak C.E.O. Joseph Boardman told the Regional Plan Association that there was something less than 20 years before one or both of the tunnels would have to be shut down.
The Access to the Region's Core project to build a set of parallel tunnels began construction in June 2009 to supplement the North River Tunnels, but that project was canceled in October 2010 by New Jersey Governor Chris Christie citing budgets constraints. On February 7, 2011, Amtrak announced that it would spend $50-million on preliminary engineering and design work for a new tunnel project called Gateway, estimated to cost $13.5-billion.
As with several tunnels under the East River, one of the North River Tunnels was flooded by the unprecedented storm surge from Hurricane Sandy. This was the first time either the North River or East River Tunnels were flooded. In May 2014 Amtrak CEO Joseph H. Boardman warned that the tunnels would likely need to be shut for repair within the next 20 years. The storm damage triggered or accelerated the deterioration which includes damage to the overhead wires and electrical systems, the tunnels' concrete bench walls and drainage systems.
^Hewett, B.H.M. (1912). "The North River Division". History of the Engineering Construction and Equipment of the Pennsylvania Railroad Company's New York Terminal and Approaches. New York: Isaac H. Blanchard Co. pp. 35–53.