A major new chapter has begun on one of the largest construction projects in the United States, with tunnel boring set to begin on the $16 billion Hudson Tunnel Project linking New Jersey and New York.
The project has reached the point where its first tunnel boring machine is preparing to begin excavation, marking the start of a major underground construction operation beneath the Palisades in New Jersey.
The new rail tunnel will eventually provide an additional connection between New Jersey and New York Penn Station and is expected to serve more than 200,000 daily passengers.
First Tunnel Boring Machine Set To Begin Excavation
The first tunnel boring machine is expected to begin digging in the coming days, with a second machine launching soon afterwards.
The two machines will initially excavate approximately 5,100 feet through hard rock beneath the Palisades, travelling from the tunnel portal in North Bergen to the Hudson County Access Shaft in Weehawken.
According to the Gateway Development Commission, the machines are expected to advance at roughly 30 feet per day, including scheduled maintenance periods.
The machines are expected to reach the access shaft approximately one year after launch.
A New Rail Tunnel Beneath The Hudson
The construction milestone is significant because the project will create the first new rail tunnel beneath the Hudson River in more than 100 years.
The existing North River Tunnel has been in service since 1910 and remains a critical part of the rail connection between New York and New Jersey.
The Hudson Tunnel Project is designed to build two new rail tubes beneath the river while also supporting the eventual rehabilitation of the existing tunnel.
Engineering On A Huge Scale
The first pair of tunnel boring machines are specialist single-shield machines designed to excavate through hard, dry rock.
Each machine has a cutterhead measuring approximately 28 feet 8 inches in diameter and a trailing gantry extending around 500 feet.
Each weighs more than 1,680 tons.
As the machines move forward, rotating cutterheads break the rock into smaller pieces. The excavated material is then transported through the machine and removed from the tunnel.
At the same time, an erector system installs precast concrete segments to create the permanent tunnel lining behind the machine.
This allows excavation and tunnel construction to take place as part of the same continuous operation.
From The Palisades To Manhattan
The first two machines will not complete the entire tunnel.
Once they reach the Hudson County Access Shaft in Weehawken, they will be removed from the excavation and replaced by a second pair of tunnel boring machines.
Those machines will be designed for the different ground conditions encountered beneath the Hudson River and will continue construction towards Manhattan.
Overall, the new Hudson Tunnel will involve nearly five miles of tunnel boring as part of approximately nine miles of new passenger rail infrastructure.
Nearly Three Years Of Construction Work
Although the tunnel boring operation is only now getting underway, construction on the wider project has been progressing for almost three years.
Work began in late 2023, including construction of a new bridge supporting Tonnelle Avenue and excavation of the launch box required for the tunnel boring machines.
While construction crews prepared the sites in New Jersey, the huge machines were being manufactured.
Each machine contains almost 100 complex components and took more than a year to manufacture.
Following factory testing in late 2025, the machines were dismantled, transported to New Jersey and reassembled at the construction site.
Workers have since carried out further testing and preparation ahead of the launch.
A Major Construction Operation
The first phase of tunnel boring is being delivered by Schiavone Dragados Lane JV as part of the Palisades Tunnel Project construction package.
The Port Authority of New York and New Jersey is managing delivery of the construction package in partnership with the Gateway Development Commission.
The Hudson Tunnel Project is being delivered through ten construction packages, with multiple packages now underway.
Once completed, the wider project will create new rail capacity between New York and New Jersey while allowing the existing North River Tunnel to undergo major rehabilitation.
Building For The Future
The start of tunnel boring represents a significant construction milestone for the Hudson Tunnel Project.
After years of planning, engineering, site preparation and manufacturing, the project is now moving into one of its most technically demanding stages.
The new tunnel is scheduled to open for passenger service in 2035, while rehabilitation of the existing North River Tunnel is expected to be completed in 2038.
For the construction industry, the project provides a major example of large-scale underground engineering, combining tunnel boring, concrete construction, excavation, specialist machinery and complex transport infrastructure across New York and New Jersey.
Source: Governor of New York / Gateway Development Commission
Image Source: Governor Kathy Hochul Official Flickr