COWI to Lead Design for New York’s 2nd Avenue Subway Expansion – Phase 2 Tunnelling and Structural Shell 

New York, NY — COWI has been appointed lead designer by Connect Plus Partners (Connect+) as part of the design build contract for Phase 2 – Tunnelling and Structural Shell of the Second Avenue Subway, one of the largest ongoing transit infrastructure projects in the United States. The Second Avenue Subway program is designed to deliver a modern, efficient, and attractive transit system, with the primary goals of improving access on Manhattan’s East Side—particularly for the East Harlem community—reducing congestion on the existing 4-5-6 line running under Lexington Avenue, and enhancing mobility for residents, workers, and visitors across New York City. The $1.972 billion design build construction contract, awarded to Connect Plus Partners—a joint venture of Halmar International and FCC Construction—will extend the Q Line north from 96th Street to 125th Street, delivering critical new rail capacity and multimodal connections in Manhattan. 

Phase 2 comprises approximately 1.5 miles of twin running tunnels, station shell construction at 116th and 125th Streets, and reuse of an existing tunnel segment originally built in the 1970s, providing significant savings. The project also includes above-ground ancillary buildings for ventilation, mechanical, and electrical systems, with opportunities for ground-floor retail and community uses. The contract awarded to Connect + and COWI includes design, engineering, scheduling, coordination and construction of the tunnelling and structural shells that will make up Phase 2 of the Second Avenue Subway Program. 

Phase 2 is a transportation option that is long-awaited by the residents and businesses of East Harlem. This project will restore a subway line to the neighborhood, adding three new ADA-accessible stations at 106th, 116th, and 125th Streets. It will significantly improve mobility for commuters and residents of East Harlem, reduce congestion on the 4-5-6 line, and enhance overall system reliability. 

Thomas Dahlgren, Executive Vice President, COWI North America, said: “Phase 2 of the Second Avenue Subway is one of the most significant infrastructure projects in the country. By extending service north to 125th Street, MTA is restoring rapid transit to East Harlem for the first time in more than 80 years, reducing crowding on the current subway line under Lexington Avenue, and improving daily mobility for more than 100,000 riders. 

“This is a technically complex job in one of the world’s most challenging underground environments. Our role is to bring the depth of COWI’s global tunnelling and underground design expertise to ensure constructability, safety, and efficiency are embedded in every stage of delivery. With 50 years of U.S. experience and the support of more than 450 tunnel design professionals worldwide, we have one of the largest and most specialized teams in the industry. That scale and knowledge give us the capacity to manage every aspect of design for a project of this size and importance.” 

As lead designer for Phase 2, and with support from a team of design subconsultants, COWI will apply its expertise in tunnel design and transit facility rehabilitation to manage all aspects of the project scope. This includes bringing industry knowledge, innovation, and technical depth to one of New York City’s most significant infrastructure investments. 

Construction is expected to begin in early 2026, with tunnel boring operations launching in 2027 and overall contract completion anticipated in 2030.