New York City, New York – Global engineering and design firm Cowi has been selected as lead designer for Phase 2 of the Second Avenue Subway. The project , valued at nearly US$2 billion, will extend the Q Line north from 96th Street to 125th Street in East Harlem. The extension restores subway service to East Harlem for the first time in more than 80 years, helping reduce crowding on the Lexington Avenue 4-5-6 line.
Route, Scale & Teamwork
The extension will include three new stations and 1.5 miles of twin tunnels. Cowi will report to the joint venture Connect Plus Partners, a collaboration between Halmar International and FCC Construction, which holds the $1.97 billion design-build contract. The plan also reuses an existing tunnel built in the 1970s to cut costs.
Above-ground elements will include electrical, mechanical, and ventilation buildings. There will also be space in some ground-floor areas for retail and community-oriented uses.
Project Factsheet – Second Avenue Subway Phase 2 Extension
Designer Cowi
Contracting JV Connect Plus Partners (Halmar International + FCC Construction)
Project Cost Approximately $1.97-2.0 billion
Route Extend Q Line from 96th Street north to 125th Street, East Harlem
Distance & Tunnels Approximately 1.5 miles of twin tunnels
Stations Three new stations
Additional Work Reuse of 1970s tunnel, ventilation & mechanical systems, retail ground floor
Start of Construction Early 2026
Tunnel Boring Start 2027
Target Completion 2030
Riders Impacted Over 100,000 daily riders; reduce pressure on Lexington Avenue lines 4-5-6
When It Will Happen & What to Expect
Work begins in early 2026, with tunnel boring set to start in 2027. Completion is targeted for 2030. Authorities say the extension will significantly improve transit access and relieve congestion on nearby lines.
Why the Extension Matters
This subway extension marks a major milestone for New York’s transit infrastructure, especially as East Harlem has gone more than eight decades without direct subway service. Once complete, the project is expected to deliver faster and healthier commutes for over 100,000 daily riders who currently rely on alternate, overcrowded routes. Alongside initiatives like USDOT and Amtrak’s $7 billion redevelopment plan for New York Penn Station, the effort underscores the city’s push to modernize and expand its transportation backbone for the future.
It also illustrates how urban areas facing capacity overload are choosing major investment in underground transit over surface fixes. Designing with reuse of old tunnel segments and adding community-friendly features shows how big infrastructure can be cost-efficient and socially beneficial.
Comparisons & Context in U.S. Transit Growth
While many U.S. cities debate suburb or highway expansion, New York continues pushing core urban transit. Comparisons emerge with other major transit expansions like LA’s Purple Line, Seattle’s Light Rail, or Boston’s Green-Line Extension. New York’s choice to build deep transit tunnels again places it among cities doubling down on underground transit.
Budget discipline appears baked into this project: reuse of earlier tunnels, lead designer selection already done, and a firm timeline. These are often challenge points in large transit projects. The successful execution of Phase 2 could serve as a model.
This extension project stands out for its blend of civic benefit, smart reuse of older infrastructure, and strong timeline commitment. It highlights how big-city transit authorities are pushing beyond incremental upgrades, aiming instead for transformative transit.
