Rail & Transit Engineering

Metro-North Railroad’s (MNR) autotransformer substations on the New Haven Line date back to the late 1970s. They were built to support the conversion of the line from 25 Hertz, 11,000v catenary to 60 Hertz, 12,500v. The conversion took place in late 1986 and the system has performed well for almost 40 years.

As part of MNR’s policy of maintaining its physical plant in a state-of-good-repair, it determined several years ago that these substations had reached the end of their useful lives. The autotransformers have tolerated thousands of short circuits due to faults on the catenary system. The original vacuum circuit breakers are out of production and spare parts are scarce. In addition, the substations are open air outdoor facilities that are exposed to the elements, which is an inherent safety risk for the employees who maintain them.

Under this contract, the Consultant Team designed new replacement substations at Mamaroneck (128) and Harrison (178), NY. MNR chose a state-of-the-art prefabricated “metal clad indoor substations” for the replacements, which they have used as replacements elsewhere on the New Haven Line. All substation apparatuses are located inside the building except for the autotransformers.

Garg Consulting Services, Inc.’s tasks on this project included:
• Providing technical advice and guidance on substation operations.
• Providing input in drawing design and substation layout.
• Foundation design for the substation vaults and autotransformers.
• Assisting in developing specifications for new equipment and structural items or work.
• Providing guidance on constructability, scheduling safety, and maintainability.
• Providing QA/QC on design and construction.