T&TI provides a snapshot of progress across a number of tunnelling projects in the US that range from transport projects in New York, Virginia and California to drainage tunnels in Ohio and Michigan.
NEW YORK
Hudson
The Hudson Tunnel Project delivery partner model has been expanded by the Gateway Development Commission (GDC) for the project in New York. As a special-purpose entity with the mandate to build the Hudson Tunnel Project, the GDC has a limited number of staff by design. GDC has oversight of the project while its delivery partner – MPA Delivery Partners – provides management and construction management support. This has allowed GDC to significantly accelerate construction across five active sites.
Since GDC awarded the contract to MPA Delivery Partners, a JV of Parsons Corporation, Arcadis of New York Inc, and Mace North America Ltd, in March 2024, GDC has:
- secured full funding for the Hudson Tunnel Project;
- awarded contracts for three construction packages, including the first construction project that involves tunnel boring;
- advanced the first Hudson Tunnel Project construction package – the Tonnelle Avenue Bridge and Utility Relocation Project – toward ontime completion in the coming weeks;
- procured and overseen manufacturing of the two TBMs that will build the section of the new tunnel in New Jersey;
- managed the procurement process for four additional construction packages, including two that will be awarded in the next six months.
The GDC said expanding its use of the delivery partner model enabled it to retain the team and build on the success so far by adding engineers, project managers, planners, safety experts, and other key personnel, bringing MPA’s support to 350-400 full-time equivalents over the next five years. The resolution allocates up to US$665 million for this new scope of work. The MPA Delivery Partners’ initial contract term ends in 2030, with the option for three subsequent three-year renewals.
New York GDC Commissioner and co-Chair Alicia Glen, New Jersey GDC commissioner and co-Chair Balpreet Grewal-Virk, and GDC Amtrak Commissioner and Vice-Chair Tony Coscia said the delivery partner model was an innovative approach to project delivery that had brought together the best of the industry to ensure the Hudson Tunnel Project stayed on track.
They said the approach with a Public-Private Partnership (P3) has made GDC “nimble, flexible, and innovative while staying on scope, schedule, and budget.”
GDC CEO Tom Prendergast said: “The delivery partner model enables GDC to bring in the right experts and resources for each aspect of this huge, multifaceted project while remaining a lean, efficient organisation.”
“The model is working well,” he added. “The MPA team has integrated seamlessly into our day-to-day operations, and the results speak for themselves.”
East River
Also in New York, bench wall demolition was recently undertaken on the East River Tunnel (ERT) Rehabilitation project.
Opened in 1910, the East River Tunnel consists of four tubes connecting New York City to Long Island and New England, and is used by Amtrak, Long Island Rail Road, and New Jersey Transit trains.
The tunnel has benches running along both sides, providing critical emergency egress for passengers.
In 2012, Superstorm Sandy inundated two tunnel tubes with saltwater, nearly submerging the bench walls and as a consequence corrosion damage accelerated.
Skanska-EJ ERT JV has been performing the demolition works for tunnel owner Amtrak, which says lessons from the works will be carried forward to the Line 1 tunnel tube, in 2026.
A year ago, a JV of STV and Naik Consulting Group was awarded a construction management services contract for the East River Tunnel Rehabilitation project.
The project involves reconstructing and upgrading all tunnel systems along the rail corridor, including demolishing all existing tunnel systems down to the liner; rehabilitating the tunnel structure; replacing cable benches; installing new fire life safety systems; replacing signals and traction power; and, converting the tracks to a modern, direct fixation track system.
The rehabilitation project for the entire East River rail tunnel began in May 2025 and is due for completion in 2028.
Second Avenue
The Metropolitan Transportation Authority (MTA) recently awarded the tunnelling contract for Phase 2 of the Second Avenue Subway project to Connect Plus Partners, a Halmar International and FCC Construction JV.
The US$1.972 billion contract is the largest in MTA’s history and the second of four construction contracts for the US$6.99 billion project, which will extend the Q train from 96 Street to 125 Street and deliver new transit access to East Harlem.
The tunnel will extend from 116 Street to 125 Street and sit between 35ft (10.6m) and 120ft (36.5m) below Second Avenue. The JV will also excavate the cavern for the future 125 Street station, and in a cost-containment measure that saves the MTA US$500 million, will outfit the tunnel along the route that was built in the 1970s to accommodate the future 116 Street station.
Early work commences in late 2025, with heavy civil construction starting in early 2026 and tunnel boring expected to begin in 2027.
Phase 2’s first construction contract was awarded in January 2024 for utility relocation work. The third contract covers construction of the underground space for the future station at 106 Street and Second Avenue. The fourth, and final, contract will cover the fit-out of the three stations, at 106, 116 and 125 Streets, and the systems for train service. The contract is in design.
Second Avenue Subway Phase 2 is scheduled to open in September 2032.
Phase 1 opened in 2017. MTA said lessons learned would help to complete Phase 2 tunnelling, including addressing utility relocation upfront to reduce the risk of unexpected costs or delays.
Additional cost containment initiatives in Phase 2 include reuse of a tunnel portion built in the 1970s, early real estate acquisition, adoption of best value contract structures such as A+B contracts (designbuild), contract co-ordination, and reduction in back-of-house, ancillary space and station size.
The initiatives have saved more than US$1.3 billion.
VIRGINIA – HRBT
Main tunnelling for the Hampton Road-Bridge Tunnel Expansion (HRBT) project, in Virginia, has been nearing completion.
The project involves construction of a twin tube road tunnel with a single TBM. The parallel tunnels haven been bored sequentially – the TBM being turned around and re-launched to drive pack to the original starting point, and soon to reach that destination.
The HRBT project is being developed by the Virginia Department of Transportation (VDOT), and in a recent project update said that the TBM, ‘Mary’, was in the final stages and boring on the uphill climb through fine grained soils, such as clay. In June, the TBM set a record of 66 rings installed in a week, achieved in large part because of the work of the slurry treatment plant, which processes about 600 tons of soil per ring before the spoils are transferred to barges for transport to final disposal.
VDOT said the slurry treatment plant made “make quick work of the coarse-grained sandy soils found deep beneath the bay bottom.” It added though that the top layers of the bay stretch the plant to its limits in quickly processing the spoils, as fines require more time to separate from the slurry.
Construction of the first tube saw the TBM complete in 51 weeks, and it may be the second tube is bored slightly faster. Fit-out works are underway inside the first tunnel, including placement of the tunnel’s roadway base along the entire length of the tube, which allows completion of the tube’s new egress structures and drainage systems.
CALIFORNIA – BART
Choice of a single bore tunnel was recently confirmed for BART Silicon Valley Phase II project by the Santa Clara Valley Transportation Authority (VTA). BART Silicon Valley Phase II Extension is a 6.25 miles (10km), four-station addition to BART, connecting Berryessa/North San José station through downtown San Jose to the city of Santa Clara.
VTA’s pick of a large-diameter, single bore tunnel as preferred option for tunnelling follows a peer review by tunnelling and transit experts from major transit agencies, following which the VTA board voted in favour of the single bore as the most viable option.
The single bore solution is judged to offer the best balance of constructability, feasibility, and lower overall risk. The VTA adds that the single bore would help to avoid the high cost, complexity, and downtown disruption associated with an alternative of concurrent tunnel boring with two TBMs. This two-TBM approach would require a cut-and-cover excavation in the heart of San Jose.
The decision allows VTA to advance project design towards 60%, keep to the critical path for the tunnel construction element of the project, and meet the revenue service date.
The panel also included recommendations to ensure greater cost estimation, accuracy and budget alignment, reduce schedule delays and manage tunnel risk.
As the VTA now owns the TBM, it assumes full responsibility for its performance. To manage this risk, VTA will deploy a top-tier tunnelling team and embed Herrenknecht engineers to support operations and reduce delays. The peer review panel highlighted the limited pool of qualified contractors and skilled labour for large diameter tunnelling. VTA says it would continue early engagement with the industry to secure experienced teams and develop a contract strategy to increase bidder participation.
OHIO – COLUMBUS
Granite Construction recently completed tunnel boring with an earth pressure balance (EPB) shield on the Lower Olentangy Tunnel Project in Columbus, Ohio, being built to help to reduce combined sewer overflows into the lower portion of the Olentangy River. The TBM, ‘The Mighty Quinn’, finished 3.5 miles (5.64km) of tunnels of 13ft-diameter (4.1m) through challenging geology.
The alignment was through geology comprising sand and gravel, silty sand, cohesionless silt and clay, and a small bedrock section with boulders, cobbles, and water. The Herrenknecht EPB shield machine completed two drives and an extension for the Lower Olentangy Tunnel Project. The TBM was equipped with features including a copy cutter, anti-roll fins, an inflatable emergency seal in the tailskin, and a bentonite lubrication system.
Both drives started from the same launch shaft. After completing the south tunnel, the TBM was dismantled and returned to the launch shaft to bore the north tunnel in the opposite direction. Logistically, this sequence required the construction teams to adapt the launch plan to accommodate the ‘figure eight’ style shaft with launch angles separated by 120°. Herrenknecht praised Granite Construction’s “outstanding inventiveness and ingenuity” in mastering the challenge of the umbilicals and the layout of crucial launch machinery.
MICHIGAN – DETROIT
The Michigan Department of Transportation (MDOT) recently issued a Request for Information (RoI) to establish the primary electrical service required for the TBM launch site for a drainage tunnel, close to the I-94 freeway. The I-94 Modernisation Segment 3 Package 1 Drainage Tunnel is being built to provide a more resilient drainage solution in the area from Burns Avenue to Barrett Avenue.
The 1.1 miles-long (1.75km) soft ground drainage tunnel will have a 14.3ft (4.4m) i.d. and an estimated 49ft-78ft (15m-24m) overburden. The design-build project also includes a launch shaft, retrieval shaft, two offline drop shafts, junction chamber, pump station, adit connections, and other associated work. The subsurface conditions anticipate the use of a pressurised face TBM.
The local utility provider, DTE Energy, supplies three-phase 480V, 4.8kV, and 13.2kV services to customers in the Metro Detroit Area. MDOT wants to determine the power required for a three-phase 13.2kV primary service to provide sufficient electrical capacity to support surface works and TBM operations at the tunnel launch/mining site and proposed onsite step-down transformer capacities and configurations, including typical redundancy and protection schemes used for TBM power distribution.
