This route, known as the Lackawanna Cut-Off, ran west from Port Morris Junction in Roxbury Township near the south end of Lake Hopatcong in northwestern New Jersey (about 45 miles (72 km) west-northwest of New York City) and to Slateford Junction near the Delaware Water Gap in northeastern Pennsylvania.

[10] Through the use of fewer and less-sharp curves, no steep hills, and no grade crossings, the route was faster and 11 miles (18 kilometres) shorter than the Lackawanna Old Road, the rail line it replaced.

The DL&W constructed structures on the new line of reinforced concrete, and the roadbed itself required the movement of millions of tons of fill material using techniques similar to those on the Panama Canal.

It did not stop in Andover at this time and passed over rail lines operated by the Lehigh and Hudson River Railway and the Sussex Branch, and over U.S. Route 206 and county roads.

In May 2008, the North Jersey Transportation Planning Authority (NJTPA) approved funding to rebuild the first segment of track for restored service along the Cut-Off route between Andover and Port Morris Junction.

[12][13] After review of the submitted environmental assessment, the Federal Transit Administration issued a Finding of No Significant Impact (FONSI) for the first phase of the project to Andover on September 12, 2008.

[1] On April 13, 2022, the NJ Transit board announced the approval of an approximated $32.5 million contract for completion of repairs to the Roseville Tunnel and construction of the new Andover station.