Three tugboats sat in the dark water at the Port of Coeymans, lines taut, waiting for the tide.
Behind them on a heavy barge rode something that weighed five million pounds and stretched 400 feet from end to end.
It was a steel arch, built to carry trains.
The only way to get it to New Jersey was to float it roughly 130 miles down the Hudson River.
Then do it twice more.
Why the meadowlands left no other choice
The Hackensack River sits inside the New Jersey Meadowlands, a wide stretch of tidal marsh where the ground stays soft well below the surface. No road into the site could carry a load anywhere near 5 million pounds, and no crane on solid ground could reach far enough across the water to set a 400 foot span onto piers in the middle of a river.
The conventional answer is to assemble an arch in place, piece by piece, from temporary falsework standing in the channel. That would have meant building a scaffold in open water directly alongside the busiest stretch of passenger rail in the country.
So the crews turned the problem sideways: each arch would be assembled in a fabrication yard far upstream, driven onto a barge by heavy lift equipment, and towed to the job site as a finished unit. The bridge exists because the old one had become a daily bottleneck, carrying more than 450 daily trains and 200,000 daily passengers over the Hackensack, its swing span rotating open for boats. A fixed span removes that cycle, and no opening cycle means no stalled train on the Northeast Corridor.
A 30 hour river journey under 18 bridges
Each arch began its journey at the Port of Coeymans, just south of Albany. Three tugboats, a heavy transport barge and a spacer barge moved the 400 foot, 50 foot wide arch at an average of 5 knots, about 5.75 miles per hour. That is a measured pace for a load that size, every mile of it crossing open tidal water.
The trip took about 30 hours because the convoy had to navigate under 18 moveable and fixed bridges along the way. Each clearance had to be checked against the height of the arch as it sat on the barge, and tidal timing had to be right at every one. A few inches of extra tide at the wrong bridge would have stopped the convoy cold.
Arrivals were timed for the small hours to avoid disturbing daytime commuters. After each arch reached the site, the crew brought it through the existing Portal Bridge before jacking it 60 feet high onto the piers. That final lift was the moment every calculation converged into a single physical act.
Three floats, three winters, one bridge
The first arch float took place in November 2024, the second in January 2025 and the third in February 2025. Three separate river convoys inside three months, each one a night operation threading a 400 foot steel structure through a corridor of old bridges in winter weather on the Hudson.
Superintendent Michelle Miyaki described the coordination in plain terms: “I would equate the process to a dance because everything was heavily planned and coordinated ahead of time, especially with the weather we experienced during the arch float ins.” The Coast Guard sent an icebreaker ahead of one voyage, and jacking could only go forward when the wind held below roughly 15 to 20 miles per hour.
Together the three arches form a 1,200 foot main span sitting 50 feet above the river. That is double the clearance of the old crossing, enough for marine traffic to pass underneath without the bridge ever moving.
What the numbers prove about the method
Each set of steel arches weighs about 2,500 metric tons, and the barges were ballasted and de ballasted against the tide so the saddles could take the load. NJ Transit’s account of the first arch delivery puts the run at 30 hours from Coeymans to Kearny.
The wider job spans 2.44 miles of the Northeast Corridor. Agency figures put the materials at roughly 45 million pounds of steel and 219,000 cubic yards of concrete, with the second and final track due to move across in the fall. The crossing is a key component of the $33.7 billion Gateway Program, which aims to double rail capacity between Newark and New York City.
When the first track entered service on March 13, 2026, it marked the moment a decade of planning became a commuter’s daily reality. For a companion sense of how far a structure can travel once it is on water, the immersed tunnel boxes being built in Denmark follow a similar logic: float the element to site, then use water itself to set it where it needs to go.
The river as the only road worth taking
The meadowlands around the Hackensack are still marsh, still soft, still laced with channels that flood at high tide. That landscape ruled out land based erection schemes and pushed the team toward the one surface that could carry the weight.
A river that blocks trucks and cranes becomes, for a barge carrying a 400 foot arch, a perfectly straight road with almost no traffic. For a sense of what happens when a different difficult method meets difficult ground, the story of a stalled boring machine under the Yangtze shows how engineers respond when the machine cannot go back the way it came.
The river float worked because most obstacles were measurable in advance: bridge clearances, tidal windows, barge draft. The one variable the crews could not fix was winter weather on the Hudson, so they watched the forecast three to four days out and moved when it allowed.
The old Portal Bridge, opened in 1910 and now 116 years old, is still carrying one track until the second cutover and is scheduled for demolition in 2027. What replaces it is simpler in concept and far harder in execution: a fixed arch that never moves, assembled well over 100 miles away and floated to its final home on a winter tide.
