Northeast Corridor Line

An Amtrak Clocker leaving 30th Station in 1976

Clocker trains were started by the Pennsylvania Railroad between Philadelphia and New York; until the 1950s weekday trains departed New York and Philadelphia on the hour through the day, giving rise to the Clocker name. After the Amtrak takeover of the Northeast Corridor the no-longer-hourly "Clocker" service was targeted at commuters making local stops bypassed by the high speed Metroliner and individually named trains. During the 1990s NJ Transit contracted with Amtrak to accept monthly NJ Transit passholders on the Clocker trains. Soon the Clockers were primarily used by NJ Transit commuters with only a handful of riders taking the trains to or from Philadelphia; the Clockers were much faster (and more comfortable) than a typical NJ Transit train, but slower and more crowded than a typical Amtrak train causing the former's riders to prefer the trains and the latter's riders to avoid them.

With most Clocker riders using NJ Transit tickets, NJ Transit supplied new ALP-46 locomotives to haul the trains' Amfleet coaches; Amtrak soon discontinued the Clocker service altogether and sold the capacity slots to NJ Transit for new Trenton express trains. The Clocker last ran on October 28, 2005, and thereafter NJ Transit began several extra Trenton-New York express trips.

The Morrisville Yard is used for train layups. In 2007 NJT opened a new 19-track yard on the site of the former Pennsylvania Railroad freight classification yard across the Delaware River in Morrisville, Pennsylvania. The new yard replaced the haphazard collection of storage tracks around the Trenton Station complex. This not only increased the absolute number of trains that could be stored at the end of the line, but also reduced the number of relay movements needed to position trains in at the correct platform at Trenton. Capacity was also increased by trains no longer having to cross all four mainline tracks to access their storage tracks as the new Morrisville yard is accessed by a flying junction.

NJ Transit Northeast Corridor Line train at Trenton Transit Center

The Trenton Transit Center is the beginning of the New Jersey Transit portion of the Northeast Corridor line and the terminus of the SEPTA Trenton Line service. The Trenton station is also a major stop for Amtrak trains, serving all Acela Express and Northeast Regional trains, most Keystone Service trains, and nearly all medium and long distance trains running along the Northeast Corridor.

In 2004 the River Line light rail Trenton station opened across the street. In 2008 the station was formally renamed the Trenton Transit Center as the station was overhauled, including the complete replacement of the station headhouse and concourse structure which had last been rebuilt during the 1960s. The new station has more space for vendors and passengers.

Hamilton Station in Hamilton Township opened in 1999, costing $30 million (1992 USD).[5] With almost direct access to Interstate 295 and Interstate 95, park and ride capacity was large with 1,556 spaces available at the station's opening. Due to the popularity of the station with commuters arriving via Interstate from points south in New Jersey and Pennsylvania, a parking deck was added in 2007 with 2,066 more spaces for a total of 3,622.[6] The station has sculptures and designs from the Grounds for Sculpture, a sculpture park in Hamilton.[7]

Hamilton Station did much to alleviate the increasingly desperate parking situations in Trenton and Princeton Junction. Trenton's downtown station is hard to reach and has little space for parking; Princeton Junction has no direct access to a major highway and its vast parking lot had long since reached capacity. The Hamilton Station was built for New York area commuters traveling increasing distances to work. Its direct freeway access and ample parking proved a hit with riders and it is one of the busiest stations on the New Jersey Transit system. The conversion of the nearby American Standard factory into transit oriented development led to further ridership gains. A new NJ Transit bus garage was also built within the station complex replacing an older garage formerly used by NJ Transit, and Mercer Metro within the City of Trenton.

The Metropark rail station project was initiated by NJDoT in 1968 as part of a plan accommodate businesses and commuters that were fleeing the old urban cores. The station opened in 1971 next to the Garden State Parkway for easy access by automobile; nearby stations at Iselin and Colonia closed soon after. The new station was also designed with the new Metroliner Service in mind with high level platforms and a large business park to make the new station a destination in itself. To allow Metroliners and other express trains to stop at Metropark new crossovers were installed in the 1980s on either side of the station to allow trains on the inner express tracks to pull over and stop at the two side platforms.

Newark Liberty International Airport Station was built in conjunction with the Port Authority of New York and New Jersey, the owner of Newark Liberty International Airport. This station allows passengers to connect with AirTrain Newark, the airport's monorail. The station opened in late 2001 and was part of a larger project to increase capacity south of Newark Penn Station. Along with the station's two island platforms, two tracks were added for a mile east and west of the station, bringing the number of tracks on this section of the corridor to 6. This allows some local trains to be passed by NJT express and Amtrak trains.

The Waterfront Connection opened in 1991, allowing eastward trains from the ex-PRR Northeast Corridor to connect to ex-DL&W Morris and Essex Lines to Hoboken Terminal. No NEC trains serve Hoboken Terminal as of January 2010 (in the 1990s there was one Hoboken-Trenton train a day) but a few North Jersey Coast Line trains run across the connection during weekday peak hours, allowing NEC passengers to transfer. At other times, passengers must transfer using PATH.

The Kearny Connection opened in 1991, allowing the opposite connection, eastward from ex-DL&W to ex-PRR, and many Morristown Line trains now use it to reach New York Penn Station.

Opened in 2003, Secaucus Junction was built as a major transfer hub for the New Jersey Transit system. Built where the Corridor crosses over the Main/Bergen/Port Jervis lines, the station allows passengers on Hoboken-bound trains to switch to trains to New York Penn Station, and vice versa.

A new station along the NEC at North Brunswick was approved by New Jersey Transit Rail Operations in 2013, but has not opened.[8]

NJT currently originates trains to New York during peak hours from the Jersey Avenue station in New Brunswick. The agency plans to build a flying junction and balloon loop called the Mid-Line Loop south of a new station south of Jersey Avenue in North Brunswick, allowing trains to turn around, enter and leave the Northeast Corridor without crossing over tracks.[9]

In January 2014, NJT awarded a $7.64-million design and engineering contract to develop a "train haven" and re-inspection facility where equipment could be stored during serious storms at an expanded and reconfigured County Yard in New Brunswick following severe flooding after Hurricane Sandy, which demonstrated the vulnerability of the agency's facilities to flooding.[10][11]