Design Build for MTA-MNR New Haven Line AC Substations in Harrison & Mamaroneck

This Metro North (MNR) design build project will replace two substations on the New Haven Line in Mamaroneck (128) and Harrison (178). Rebuilding the substations will improve the power supply capacity and resiliency of the traction power system, along with safety and reliability improvements.

Metro-North is transitioning to indoor AC autotransformer substations for increased resiliency, weather resistance, and employee safety. The existing substations are outdoor switchyards with overhead wire installed in the 1980s. This design is not considered safe, weatherproof, or aligned with today’s standards.

Garg Consulting Services, Inc. (Garg) is providing electrical engineering services for the project in both pre-construction and construction phases, including but not limited to:

• Site surveys, final design, obtaining required permits, preparation of required specifications
• Site excavation and disposal of all unused soil per environmental guidelines.
• Installation of required underground electrical, signal, communication, and utilities.
• Preparation/construction of foundations, cable, vaults, grading, structure, steel grating, platforms, prefabricated substation buildings, substation equipment, duct bank infrastructure, and interconnecting cables.
• Obtaining approval for each prefabricated substation & arranging for fabrication prior to delivery.
• Identifying and commissioning of required electrical utility services.
• Performing a short circuit, protective relay/device coordination study, step and touch potential study, and arc flash analysis.
• Testing & commissioning of each substation before connecting it to MNR’s traction power system, with the ability to revert to existing substations’ power in case of emergency.
• Obtaining approval for qualifications and factory acceptance tests.
• Disconnecting, demolishing, and removing the existing substation per MNR’s directives.
• Upgrading the existing overhead bare feeder wires.
• Performing air gap work for catenaries of all four tracks at the Mamaroneck substation.