Bergen Tunnels

Prior to construction, the Morris and Essex Railroad, a predecessor of the DL&W, used the Long Dock Tunnel, owned by the Erie Railroad, to pass under the Hudson Palisades. After issues of congestion and competition arose, the DL&W decided to build its own tunnel for what is commonly known as its Morristown Line.^[2][3] Construction of the North Bergen Tunnel began in 1873; it came into service in 1877.^[4] The South Bergen Tunnel opened in 1910,^[5] soon after a new Hoboken Terminal was inaugurated. Both tunnels are approximately 4,200 ft (1,300 m) long,^[6][7] and have two short segments of open cut as well as ventilation shafts.^[8]

In 2001, New Jersey Transit contracted JV Merco-Obayashi for the rehabilitation of the partially brick-lined North Bergen Tunnel.^[9] This included the stabilization of the two open cuts. The five ventilation shafts were stabilized and backfilled. Brick was removed so that the tunnel could be enlarged using drill-and-blast methods, following which it was relined with shotcrete. A drained membrane waterproofing system was installed before a final lining of concrete was cast-in-place.^[8] In addition to waterproofing ceilings and walls, new electrical, signal and ventilation systems were installed as were new emergency exits. New tracks were affixed directly to a new concrete floor.^[10]

There are unfunded plans to rehabilitate the South Bergen Tunnel as it suffers from water leakage and icicle formation during the winter months.^[11]

The tunnels are part of New Jersey's state historic preservation office historic district, designated the Old Main Delaware, Lackawanna and Western Railroad Historic District.^[12] They were documented in 2001 for the Historic American Engineering Record.^[13]