The charter was amended to allow placing piers in the river by 1872 (despite fierce opposition from navigation interests), and the company began raising funds.

Through the influence of Andrew Carnegie, Pennsylvania Railroad president J. Edgar Thomson was persuaded to invest in the project.

At the state line, an extension of the planned Massachusetts Central Railroad would connect, taking traffic to Boston.

Grading began on the various lines, known as the South Mountain and Boston Railroad, and the cornerstone was laid for a bridge pier at Poughkeepsie.

In the meantime, the P&NE (PA Division) was successful in laying one and one-sixth mile (2 km) of track to the east of Wind Gap about 1880.

In early 1883, a dispute erupted with the Wind Gap and Delaware Railroad over the tracks between Pen Argyl and Bangor, which the PS&NE wanted to use.

Around that time, various other companies were chartered to build the line over the Poughkeepsie Bridge, and in 1889, the Central New England and Western Railroad was completed.

It was originally planned to extend beyond Pine Island to Campbell Hall, the west end of the existing Poughkeepsie Bridge line.

Part of the main line between Benders Junction (the crossing of the original L&NE and the L&L) and Pen Argyl was abandoned in 1905, with the new route using the L&L and WG&D.

On July 24, 1912, a new extension opened, splitting from the main line at Danielsville, Pennsylvania, and running west to Tamaqua to directly serve the LC&N.

Although the LNE was still profitable, the rapid decline of the anthracite coal business was seen on the horizon and the decision was made to cease operations.

To railfans, the L&NE is best remembered for its diesel motive power, which consisted almost entirely of models built by Alco, excepting two Whitcomb Center Cab switchers, numbers 601 & 602.