The Metropolitan Transportation Authority project is designed to improve 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.
The US$1.972bn 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 to deliver new rail capacity and multimodal connections in Manhattan.
Phase 2 comprises approximately 2.4km of twin tunnels, station shell construction at 116th and 125th Streets, and reuse of an existing tunnel segment originally built in the 1970s. 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, co-ordination and construction of the tunnelling and structural shells.
Thomas Dahlgren, executive vice-president, COWI North America, said Second Avenue Subway Phase 2 was one of the most significant infrastructure projects in the US and 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 US experience and the support of more than 450 tunnel design professionals worldwide, we have one of the largest and most specialised 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,” said Dahlgren.
Construction is expected to begin in early 2026, with tunnel boring operations launching in 2027 and overall contract completion anticipated in 2030.
