Raritan Valley Line

Most of the line follows the main line of the former Central Railroad of New Jersey. Historically, CNJ trains ran on this line, as part of its Lehigh-Susquehanna Division, from Scranton, Wilkes-Barre, Allentown, Bethlehem and Easton in eastern Pennsylvania through Elizabeth and Bayonne to Jersey City. In peak years of service the line was the basis for trains such as the Queen of the Valley and the Harrisburg Special, reaching as far west as Harrisburg, Pennsylvania.

Until 1967 CNJ service terminated at the company's Communipaw Terminal in what is today Liberty State Park.[3] This station, which was also served by Reading Company trains to Philadelphia and B & O service to Washington, D.C., and beyond, had connections by chartered bus or ferry into Manhattan.

At the end of April 1967, the Aldene Connection opened, connecting the CNJ main line to the Lehigh Valley Railroad (now Conrail's Lehigh Line), and trains were re-routed to Newark Penn Station on the Northeast Corridor via Hunter Connection. This allowed CNJ to end the ferry service between Jersey City and Manhattan, which was losing money.[4]

The former CNJ Main Line was conveyed to Conrail on the former's bankruptcy in 1976. Conrail sold the line to the state of New Jersey in 1978 but continued to operate commuter service under contract.[5] Service on the line was cut back from Phillipsburg to High Bridge on January 1, 1984.[6]

Trains initially could not go beyond Newark Penn Station to New York Penn Station because the locomotives were diesel-powered, and diesel locomotives cannot operate in the North River Tunnels. The introduction of ALP-45DP dual-mode locomotives allows for direct service to New York Penn Station.[7] Limited service to New York Penn Station started as a pilot program on March 3, 2014. Select trains provide one-seat rides to New York. This original "pilot project" schedule has been subsequently expanded to include additional trains, but is limited to off-peak hours due to capacity issues in the Hudson River tunnels.

Unlike the Northeast Corridor, the majority of stations on the Raritan Valley Line are not wheelchair accessible. Newark Penn Station, Union, Cranford, Westfield, Plainfield, and Somerville are accessible high-platform stations. Roselle Park has a high platform but does not have a ramp or elevator to the street.[8]

In September 2018, all Raritan Valley Line service was truncated to Newark Penn Station to allow for positive train control installation. Direct service to New York resumed on November 4, 2019.[9]

White House station

Since it is not electrified, the Raritan Valley Line requires diesel locomotives. The locomotives originally consisted of the GP40PH-2(A and B) and Alstom PL42AC with a 5- or 6-car set of Comet series coaches. Since late 2008, Bombardier Multilevel Series Coaches were added and displaced most of the Comet coaches. As of late 2013, the trainsets' consist use an ALP-45DP and a 6- to 8-car set of Multilevels. However, some occasional trains use the Comet coaches coupled with a PL42AC or an ALP-45DP. Some GE P40DC locomotives were occasionally used on the line between 2007-2009.

With the initiation of select, direct, service to New York Penn Station on the Raritan Valley Line in March 2014, dual-mode Bombardier ALP-45DP locomotives (combination diesel and electric power) were added to the RVL rolling stock to incorporate the "one seat ride" between Raritan/High Bridge and Penn Station in New York. Switching of modes is performed at Newark.

The line's rolling stock is stored at the Raritan Yard, the line's only rail yard, located just west of the station of the same name. All eastbound trains change crews here and trains are normally stored here overnight. This is also one of two fueling facilities for NJT locomotives (the other is at Hoboken Terminal). All trains terminating in Newark head to the Meadows Maintenance Complex in Kearny, New Jersey to be stored.

In May and June 2018, NJ Transit leased 10 MARC coaches to be exclusively operated on the Raritan Valley Line. These cars have since been sent back to MARC.[10]

• Bernhart, Benjamin L. (2004). Historic Journeys By Rail: Central Railroad of New Jersey Stations, Structures & Marine Equipment. Outer Station Project. ISBN 1891402072.