When the railroad opened in 1856, the Van Nest Gap Tunnel was not yet completed, and a temporary track was used.

While the Warren Railroad was straight from the DL&W's former terminus at the Delaware River to the CNJ, its route to the M&E was circuitous.

After the DL&W lease, a third rail was added for 66 miles (106 km) from Washington eastward to Hoboken from 1869-1870.

The Lackawanna Cut-Off was built to minimize grades and curves, and to avoid the operational problems of the Warren Railroad.

Hurricane Diane caused extensive damage to the line at Delaware and Manunka Chunk in 1955.

While the Blairstown Railway was a partial thoroughfare for the New York, Susquehanna & Western Railroad and the Lehigh & New England Railroad, the section from Delaware to Hainesburg was just a vestigial branch line known as the Delaware Branch, which was abandoned in 1928.

Passenger service ceased in 1952, and the tracks north of Belvidere to the junction were washed out by Hurricane Diane in 1955.

The Lehigh and Hudson River Railway crossed beneath the Warren Railroad south of Bridgeville, without an interchange.