Tunnel boring for $16B Hudson River tunnel project begins
Credit: Don Pollard/Office of Gov. Kathy Hochul on Flickr
After more than a decade of planning, work on a new rail tunnel connecting New York and New Jersey has finally begun. Gov. Kathy Hochul on Monday announced the start of tunnel boring for the Hudson Tunnel Project, with the first of two hulking tunnel boring machines (TBMs) set to begin carving through the Palisades Cliffs and the second to follow soon after. The milestone comes after nearly three years of construction work and a months-long funding freeze by the Trump administration that briefly halted the project before a federal court ordered the funding restored.
Part of the broader Gateway Program, the $16 billion Hudson Tunnel Project is constructing a new, two-tube rail tunnel under the Hudson River while rehabilitating the deteriorating tunnels that connect New York and New Jersey. More than 110 years old, the existing tunnels suffered extensive damage during Superstorm Sandy in 2012 and have continued to deteriorate since.
Despite its aging condition, which requires constant maintenance that frequently leads to delays, the tunnel is a critical component of the economy. If it were to shut down for just one day, it would cost the nation’s economy roughly $100 billion, as 6sqft previously reported.
To excavate the new tunnels, the Gateway Development Commission (GDC) announced last August that it had ordered two TBMs from Germany-based manufacturer Herrenknecht. Measuring nearly 29 feet in diameter and more than a football field in length, the machines are designed to bore through the rock beneath the Palisades.
The first set of machines are “single-shield machines,” designed for efficient tunneling through hard, dry rock.
Each machine’s cutterhead is 28 feet, 8 inches in diameter, while its trailing gantry extends roughly 500 feet. The machines each weigh more than 1,680 tons.
As they bore through the rock, rotating cutterheads fitted with disc cutters press against the rock face, breaking it into chips. Buckets trailing the TBMs collect the excavated rock and transport it through the trailing gantry before it is hauled out of the tunnel, according to a press release.
While the machines advance, an erector arm places precast concrete segments to form the permanent tunnel lining. Hydraulic thrust jacks then push the TBMs forward, bracing against the edges of the completed tunnel lining.
Following final testing after Monday’s ceremonial launch, the first machine will begin boring, followed by the second soon after. The two machines will dig about one mile through the hard rock beneath the Palisades Cliffs in NJ to the Hudson County Access Shaft in Weehawken.
The two machines are expected to carve roughly 30 feet of tunnel per day, including scheduled pauses for maintenance. In approximately one year, they are expected to reach an access shaft in Hudson County, where they will be removed and replaced with a second set of TBMs that will bore the section beneath the Hudson River.
During a Monday press conference announcing the start of construction, several officials framed the milestone as a rebuke of the Trump administration’s efforts to halt the project. In October 2025, amid a federal government shutdown, funding for the Gateway Project stopped flowing despite a previous $12 billion commitment made under the Biden administration.
After a $500 million line of credit from Bank of America that allowed the project to proceed ran out, work temporarily ceased in February. NY and NJ filed a lawsuit seeking to force the Trump administration to release the funds, prompting an appeal that delayed the reversal until later that month, when the administration released the funds and construction resumed.
“Building a new rail connection across the Hudson River has been a dream for over a generation, one that would improve reliability and resilience for over 200,000 daily riders who power our economy,” Hochul said.
“We fought and beat efforts from the Trump administration to halt the Gateway project and today, that dream becomes a reality, with state of the art machinery operated by expert union workers starting their journey through soil and bedrock under the Hudson to Penn Station.”
Concluding her statement, Hochul said the project “will be done” by 2034, while acknowledging that some other officials have said 2035.
Work on the tunnel project’s first phase began in November 2023, with crews raising Tonnelle Avenue to provide 19 feet of clearance above the train tracks and building a bridge leading into the new tunnel’s entrance, as 6sqft previously reported.
The first phase of tunnel boring is being led by Schiavone Dragados Lane JV as part of the Palisades Tunnel Project construction package. The Port Authority of NY and NJ is overseeing the package’s delivery in partnership with the GDC.
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