NJ: Workers racing to build the Hudson River rail tunnels face sweltering summer heat

In the year since the Hudson River rail tunnel project got its record-breaking $6.8 billion federal grant, armies of workers spread across five locations have battled extreme weather and the realities of urban construction as they build the $16 billion Gateway tunnel.

Most of the work by the 11,200 construction workers, who have faced sweltering heat and freezing cold, has been out of the public view.

The workers are the stagehands and set builders preparing for the big show that will be the first tunnel drilling project under the Hudson River in over a century.

The worksites vary: From rock drilling at the soaring Palisades in North Bergen to hammering out a deep, giant trench wedged between Hudson Yards that is crisscrossed by the historic High Line elevated walking trail.

And one project isn’t even on land, it’s in an artificial rectangular dam created in the middle of a turbulent Hudson River.

“When it’s done, we’ll have four good-as-new tubes to serve for the next 100 years,” said Steve Sigmund, Gateway Development Commission spokesperson. “Ten mega projects will be made into one.”

A tour of the five sites taken on Tuesday revealed each construction project faces unique challenges in the nation’s most densely populated region.

First over the finish line

The first project undertaken by the fledgling Gateway Development Commission, that is charged with overseeing the 10 tunnel projects, is building a new Route 1&9/ Tonnelle Avenue bridge for traffic and utilities over the new tracks to the mouth of the new tunnel in North Bergen.

“Stage two will be complete today (Tuesday). We’re actually shifting traffic this evening. It’s an exciting day for us,” said John Schweppenheiser III, Naik Group senior vice president, consulting project managers. “It’s a great milestone, it will shift traffic to the west bridge and that will allow us to complete the third and final stage of the project.”

The hot and humid air at the Tonnelle Avenue Bridge on Tuesday was permeated by the alternating sounds of hammering construction machines and blaring train horns warning their entry and exit from the nearby 115-year-old Hudson River tunnels.

This was the site of the only work done on the ARC tunnel project that Gov. Chris Christie canceled in October 2010, but the cavernous bridge bears no evidence of that failure. The partially-completed bridge was demolished and material recycled after being buried under soil for 10 years, Schweppenheiser said.

On Thursday morning a structure holding up the north bound lanes behind the completed stage 1 and 2 bridges will be broken through to start work on the third stage, he said.

Drill, baby, drill

Next to the bridge, workers are preparing a site at the foot of the rocky Palisades for the arrival of two monstrous-sized tunnel boring machines which will perform the drilling of the first twin 28-foot diameter tunnels through 1 mile of rock through the Palisades under Paterson Plank Road in North Bergen.

“We’re building a concrete wall three quarters of the way to bedrock. We’ll drill and blast out the bedrock another 40 to 50 feet and that will be the portal face for the tunnel boring machines,” said Kurt Paxton, supervisor for Schiavone Construction. “The machines have to start and end in rock.”

The components that make up the tunnel boring machines will be lowered to the dig site in a steel basket, assembled and be ready to start drilling in about a year, Paxton said. As they drill, a precast tunnel lining will be installed.

Ultimately, a second set of tunnel boring machines will be deployed that are suitable for chewing through the softer soil under the Hudson River to New York. That separate contract to drill the main tunnel, expected to be awarded in early 2026, Sigmund said.

“It’s not a lot of time,” Paxton said.

Under the High Line and Hudson Yards

Construction of an 80-foot deep third tunnel box under the Hudson Yards development, taking trains to and from Penn Station, is currently a giant trench. Many massive yellow steel braces span it to reinforce the rock walls and protect workers and machines hammering away and digging rock below street level to deepen it.

The third stage will connect with the first two sections built by Amtrak in 2018, which now support the completed portion of Hudson Yards.

The tunnel box has been built using a process called cut and cover, similar to what was used on many of Manhattan’s subways. It’s 56% toward a late 2026 completion date, said LeRoy Antoine, senior project manager for Amtrak.

Work started by digging a deep trench for the tracks, reinforcing it and covering it over. The concrete tunnel box has to support the remainder of the Hudson Yards development to be created over it.

Braces will be carefully removed a section at a time, to allow the pouring concrete slabs from the bottom up to the roof, and the tunnel box will be filled with sand for temporary support until the main tunnel is built from the river.

Care had to be taken not to disturb electrical service to the Long Island Rail Road train yard next door, or the High Line. Long, bus-length concrete beams were built across the trench to serve as temporary foundations to support the High Line trestles, Antoine said.

“We have (seismic) monitoring points so we know if the High Line moves a tenth of an inch,” he said.

Fighting the mighty Hudson River

The other Gateway project tourists can see from the High Line is the Hudson River Ground Stabilization project that involved the construction of a 1,200-foot by 100-foot rectangular coffer dam in the Hudson River.

No beavers were involved, but there are “pig barges.”

The coffer dam seems to be the most impossible project of all, involving the pounding of 150 sections of 12-foot diameter piles and metal sheeting into the riverbed to create a dry, safe space for the needed concrete work. So far, 450 of 600 piles have been installed.

The barges around the coffer dam make up a floating concrete plant. A “pig barge” stores several truck loads of concrete that is pumped into the river while muck is pumped out, river tour guide Steve Sigmund said.

The dam is necessary as the tour showed. The Hudson is a tidal river and waves aggressively slapped the tour boat from side to side at times.

“It’s a hard environment in which to do work,” he said.

The 1,200-foot-long by 100-foot-wide block of reinforced earth serves as a stable environment for the first tunnel boring machine pass through instead of the soft river bed working its way from New Jersey, and for the tunnel to climb to Manhattan.

The tunnel boring machines descend to 80 feet below the river bed and gradually climb up up a steady 2% hill that trains can handle to each Penn Station, he said.

But fish hold the ultimate authority over when work to extend the coffer dam east starts and stops. Work in the river around the coffer dam must pause from January to July when sturgeon, a native fish species, are spawning in the river.

The dance

Keeping the entire project moving is the job of Gateway Development Commission CEO Tom Prendergast who has been to this dance before, during the MTA’s problematic construction of the Second Avenue Subway and Grand Central Madison deep cavern Long Island Railroad complex.

“We learn from everything. Is there a better way?” he said.

The main issue is keeping 10 projects moving without delay. A delay in one will have a domino effect on the project that depends on the preceding project’s completion, Prendergast said.

“You don’t deliver a project of this magnitude without problems, the key is staying on top of them ... identifying problems and staying on top of them,” he said.

It also requires immediate communication to make sure the projects partners “are kept informed on what is going on with the project and if there is a concern, (to) address it immediately” Prendergast said.

Despite the turmoil in Washington, D.C., Prendergast said the tunnel continues to be supported by the Trump administration. The USDOT proposed 2026 budget contains the expected $700 million annual allocation for Gateway.