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.

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.

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.