In 1882, the Lehigh and Hudson River Railway made a deal with PRR to operate on the Bel-Del between Phillipsburg and Belvidere where L&HR's track to Maybrook, New York connects.

By the 1950s, steam locomotives had been replaced with diesel operated self-propelled doodlebugs as a cost-saving measure resulting from dwindling patronage.

On December 31, 1957, the Bel-Del was merged into the United New Jersey Railroad and Canal Company, with passenger services ending on October 26, 1960.

The chief function of the Bel-Del — bringing coal and iron ore between the LV connection at Phillipsburg with the PRR system — had long since ceased.

While the Trenton-Lambertville segment was not included in their system, Conrail retained the rest of the line from Lambertville to Belvidere, renaming it their Delaware Secondary.

In 1998, BR&W ceased regular operations into Lambertville when track was demoted to excepted prohibiting the continuation of passenger trains on that segment of the line.

The New York Susquehanna & Western Historical & Technical Society (NYS&WH&TS) started running passenger trains in 2004 between Phillipsburg and Carpentersville and has since become a successful operation.

In recent years both the NYSWHTS and the Black River Railroad Historical Trust (the entity that now runs passenger trains on BR&W) have been gradually restoring the dormant Milford and Lambertville lines.

Norfolk Southern (NS) retains ownership of the Phillipsburg-Belvidere main line after the Conrail split of 1999 with CSX Transportation.