New York City-based infrastructure firm STV and the Metropolitan Transportation Authority (MTA) have announced the completion of a new Grand Central Terminal passenger tunnel.
The project connects Grand Central Terminal to the No. 7 Subway Line’s Grand Central-42nd Street station.
As the designer and engineer-of-record, STV supported the design-build team led by Skanska. The underground connector is now fully operational.
The underground passageway will improve passenger flow between the subway station and terminal, serving over 500,000 visitors daily.
The company has also built a new staircase to the Flushing Line platform and widened existing staircases by 25% to improve customer flow between the Lexington and existing passageways.
The overall project focused on maintaining infrastructure, repairing concrete, steel, and paint defects, and upgrading fire alarms and utilities at the Flushing, Lexington, and Shuttle stations.
This is part of the larger Grand Central-42nd Street Circulation Improvement Project, aimed at enhancing passenger flow and reducing congestion.
The project, set for completion later this year, includes the replacement of eight escalators, a new fare control area, updated wayfinding, lighting, signage, and architectural enhancements on the mezzanine.
New York Governor Kathy Hochul said: “The new passageway will improve the connectivity and flow of traffic through Grand Central, and I am dedicated to bettering our riders’ transit experience and keeping New York moving.”
Construction beneath East 42nd Street and Lexington Avenue involved working near buildings, underground structures, and utilities with limited flexibility.
The team used Sequential Excavation Methods (SEM), a tunnelling technique that excavates and supports small sections to maintain ground stability.
Specialised equipment like Brokk-mounted drills and hydraulic machinery allowed for precise drilling and excavation.
Advanced 3D Finite Element Analysis was also employed to model structural reactions to real-world forces. This approach minimised ground settlement, groundwater seepage, and construction impact on utilities, STV said.
STV New York metro area manager and senior vice president Peter Pappas said: “This new tunnel is a transformative investment in the MTA’s transit network, enhancing connectivity and creating a more efficient transfer experience for millions of visitors utilising Grand Central Terminal every week.”
The American construction firm has built long-term partnerships with the MTA, contributing to projects like Grand Central Madison, Long Island Rail Road Elmont-UBS Arena Station, Mother Clara Hale Bus Depot, and accessibility improvements at New York City Subway and Staten Island Railway stations.
