Norfolk Southern Railway (NS) shares the use of the track for local freight operations between Suffern and Port Jervis.

Since 2003, MNRR immediately began a substantial track and signal improvement program in order to provide a more reliable and comfortable service, for $183 million.

[citation needed] The line, along with the Main Line through Paterson, served as a segment of the Erie Railroad's long-distance flagship trains to points west such as Binghamton, New York State's Southern Tier, Buffalo and Chicago, on daily routes such as the day train, the Erie Limited.

[11] This included service west of the Hudson River, where rail lines do not connect directly with New York City.

However, the MTA cited that it was responding to pressure by the towns to have the service moved out of the populated areas due to "traffic concerns" caused by the closures of the grade crossings.

[19][20] In April 2002, Norfolk Southern told Metro-North that it would not renew the existing trackage agreement between the two parties, which was set to expire on December 31, 2003.

[18] On January 22, 2003, the Metro-North Railroad Committee of the MTA Board approved a 49-year lease of the entire line from Norfolk Southern.

As part of the deal, Norfolk Southern would retain exclusive free trackage rights to operate freight trains over the line, and would be exempted from county and town property taxes.

The project, which was to be completed by the start of winter, was intended to improve signal reliability, reduce maintenance costs, and permit smoother rides.

The opening of Secaucus was expected to increase ridership by 1,000 people a day, but that did not materialize with changes in commuting patterns after the September 11 attacks.

[34] In a 2013 report, the MTA revealed that planning was underway for installing a second track between Sloatsburg and the Moodna Viaduct, and for the construction of a midway yard on the line.

[26] $83 million was allocated in the 2015–2019 MTA Capital Program to keep the Port Jervis Branch in a State of Good Repair.

[35] In 2017, Metro-North started its West of Hudson Regional Transit Access Study to evaluate possible improvements in the Port Jervis Line service.

As part of the study, three possible sites for a midpoint yard were evaluated: Harriman, Salisbury Mills, Campbell Hall.

[35] The passing sidings would all be at least two miles (3.2 km) long, bringing the line closer to the railroad's eventual goal of double-tracking all of it.

[36] In April 2020, work to install cab signaling on the entire line to support Positive Train Control was completed.

[38][39] Port Jervis Line trains start at Hoboken and then stop at Secaucus Junction to take passengers connecting from New York Penn Station.

Most of the Port Jervis Line trains then travel to New York State at Suffern, running non-stop or making one stop at Ramsey Route 17 station.

The stations at Sloatsburg and Tuxedo are very close to 17 and, while Harriman also has its entrance on 17, its actual platform is farther back, adjacent to the Thruway.

At Schunemunk's north end, it curves along to the Moodna Viaduct: the highest and longest railroad trestle east of the Mississippi River.

The track crosses the Wallkill River, then Interstate 84, to run parallel to NY 211 near Highland Lakes State Park for a while.

Shortly after leaving the highway's side, trains arrive at Middletown near the popular Galleria at Crystal Run shopping mall.

The siding rejoins the mainline just after the Otisville station, as trains enter a mile-long (1.6 km) tunnel under the Shawangunk Ridge: the longest on Metro-North.

Due to the arrangement between the MTA and NJ Transit, although the MTA subsidizes the service and maintains all of the facilities (except for the Suffern station), the actual operation of the line is almost totally under the control of NJ Transit–the trains are operated by NJT personnel;[27] the trains are dispatched from Hoboken and the ticket vending machines on station platforms are NJT machines, not Metro-North's.