Harold Interlocking

Harold Interlocking is a large railroad junction located in New York City. It is the busiest rail junction in the United States.[1] It serves trains on Amtrak's Northeast Corridor and the Long Island Rail Road's Main Line and Port Washington Branch, which diverge at the junction.

Harold Interlocking and Sunnyside Yard in 1977

Reconstruction work on Harold Interlocking started in 2009, as part of the East Side Access project to bring LIRR service to Grand Central Terminal. As part of the project, two tunnels for Northeast Corridor trains bypassing Harold Interlocking are being built to address congestion problems and occasional accidents.

Location and operationEdit

Harold Interlocking track map
LIRR Main Line to Woodside
(third rail power)
Third rail ends (Amtrak) ↑
Third rail begins (Amtrak) ↓
Catenary begins (LIRR) ↓
Catenary ends (LIRR) ↑
Catenary begins (LIRR) ↓
Future East Side Access
(third rail power)
to Sunnyside Yard loop
Future N.E. Corridor bypass
(catenary power)
Amtrak N.E. Corridor to Penn Station
(catenary/third rail power)
East River Tunnels track numbers
LIRR Main Line to Hunterspoint Avenue
(catenary/third rail power)
Main Line track numbers
Harold Interlocking
Outside interlocking, normally used by LIRR
Outside interlocking, normally used by Amtrak
Outside interlocking, normally used by both LIRR and Amtrak
Outside interlocking, normally not used
Track numbers at bottom of diagram correspond
with track numbers approaching East River Tunnels.[2]

The junction is located in Queens, New York, east of the East River Tunnels and next to Amtrak's and NJ Transit Rail Operations' Sunnyside Yard. During the rush hour period, over 40 trains per hour pass through the interlocking; and a total of 783 trains each weekday.[3][4] In addition to Amtrak trains, the interlocking serves the Long Island Rail Road (LIRR), whose Main Line and Port Washington Branch diverge from the Northeast Corridor at Harold Interlocking.

View from a nearby overpass
Entering the Harold Interlocking on the LIRR from the east

The complexity of the junction and the large volume of traffic has caused frequent delays and occasional accidents in this portion of the Northeast Corridor.[5][6]


The Pennsylvania Railroad built the Harold Interlocking in 1908 as part of the New York Tunnel Extension project, which built Pennsylvania Station, the North River Tunnels (under the Hudson River), the East River Tunnels and Sunnyside Yard.[3]

The interlocking was renovated in summer 1990 during a nine-week modernization project.[7] This renovation was conducted several months after a power surge caused trains to be stuck in the interlocking. Since the 1990s, Harold Interlocking has been controlled from a tower at Penn Station.[5]

East Side Access improvementsEdit

The Metropolitan Transportation Authority (MTA) began construction of several infrastructure improvements to the junction area in 2009, but a major project to redesign and rebuild the interlocking required additional funding.[8]

In May 2011, a $294.7 million federal grant was awarded to address congestion at the interlocking.[9] The work will allow for a grade-separated route between the East River Tunnels and the Hell Gate Bridge for Amtrak trains traveling to or from New England, thus avoiding LIRR traffic. Northeast Corridor trains from the Hell Gate Bridge and New England would be able to avoid the junction entirely, while trains to the Hell Gate Bridge and New England would be able to bypass a major section of the junction. As part of the project, Amtrak's car-washing facility within Sunnyside Yard, as well as several small Amtrak buildings, are being relocated. The MTA is constructing and managing the improvement project as part of the adjacent East Side Access project to bring the LIRR to Grand Central Terminal.[1] As of late 2017, the MTA estimated that East Side Access would be substantially complete in 2022.[10] By November 2018, two of three East Side Access tunnel portals had been built at Harold Interlocking, and only the centermost portal remained to be built.[11]

Work on the Northeast Corridor bypass started in 2013.[12] However, by October 2015, the tunnels were behind schedule because Amtrak and the MTA could not cooperate on track access schedules.[13] These delays ultimately raised construction costs by almost $1 billion as of April 2018,[14] and in a report that month, the MTA attributed the delays to a lack of cooperation on Amtrak's part.[15]:27–31 The work at Harold Interlocking also included the installation of a microprocessor-based interlocking logic, replacing the old relay-based one.[16][17]


  1. ^ a b "Harold Interlocking Northeast Corridor Congestion Relief Project". Capital Program. New York: Metropolitan Transportation Authority (MTA). Retrieved April 30, 2016.
  2. ^ Lynch, Andrew (2020). "New York City Subway Track Map" (PDF). vanshnookenraggen.com. Retrieved February 6, 2020.
  3. ^ a b Bibel, George (2012). Train Wreck: The Forensics of Rail Disasters. JHU Press. p. 83. ISBN 9781421406527.
  4. ^ Via, Cynthia (August 30, 2011). "Federal transit funding arrives for Sunnyside Yards". Forest Hills/Rego Park Times.
  5. ^ a b McGeehan, Patrick (May 22, 2012). "Guiding Hundreds of Trains, a Junction Named Harold". New York Times.
  6. ^ "Rail Safety Section Abbreviated Report. Case No. 6935; Date of Accident: March 29, 2002; Carrier: Long Island Rail Road; Type of Accident: Collision". Office of Modal Safety & Security. New York State Public Transportation Safety Board. October 18, 2002. Retrieved April 30, 2016.
  7. ^ Lyall, Sarah (July 3, 1990). "'Waiting for Harold,' a L.I.R.R. Saga". The New York Times. Retrieved December 1, 2018.
  8. ^ "MTA reaches two milestones on East Side Access". Railway Track & Structures. Simmons-Boardman. December 8, 2015.
  9. ^ Colvin, Jill (May 9, 2011). "New York Awarded $350 Million for High-Speed Rail Projects". DNAinfo.com. Archived from the original on May 13, 2011. Retrieved May 13, 2011.
  10. ^ East Side Access Quarterly Progress Report: October, November, December 2017 (PDF) (Report). MTA. December 2017. p. 83.
  11. ^ "East Side Access: Bringing Long Island Rail Road Service to the East Side of Manhattan LIRR Committee Report" (PDF). Metropolitan Transportation Authority. November 13, 2018. Retrieved November 20, 2018.
  12. ^ "East Side Access trackwork to speed LIRR and Amtrak trains". Railway Track & Structures. July 18, 2013. Retrieved March 15, 2018.
  13. ^ Castillo, Alfonso A. (October 3, 2015). "MTA 'megaproject' challenged by Amtrak". Newsday. Retrieved March 15, 2018.
  14. ^ Castillo, Alfonso A. (April 15, 2018). "East Side Access price tag now stands at $11.2B". Newsday. Retrieved April 16, 2018.
  15. ^ "Capital Program Oversight Committee Meeting" (PDF). Metropolitan Transportation Authority. April 23, 2018. Retrieved April 20, 2018.
  16. ^ Castillo, Alfonso A. (March 1, 2018). "MTA: Another snag for East Side Access project". Newsday. Retrieved April 16, 2018.
  17. ^ "LIRR to test upgraded signal system for East Side Access project. For Railroad Career Professionals". Progressive Railroading. April 5, 2018. Retrieved April 16, 2018.

External linksEdit

Coordinates: 40°44′55″N 73°55′37″W / 40.7485°N 73.927°W / 40.7485; -73.927