Officials broke ground Friday on the first piece of a complex and costly project to rebuild and replace the aging rail infrastructure that carries thousands of New Jersey commuters daily into New York.

Gov. Chris Christie joined members of the state's congressional delegation, and leaders from Amtrak, NJ Transit and the Port Authority of New York and New Jersey at Portal Bridge, a 107-year old span in the Meadowlands that's become a major bottleneck on the nation's busiest commuter corridor. There are some 450 train movements a day between Newark and New York.

As trains of Amtrak and NJ Transit rattled across the structure, the officials spoke of the years-long process of just getting to this point in a process that could still take decades and tens of billions of dollars to complete, with funding sources yet to be identified.

"Lots of things have to fall into place to make this work," said Sen. Cory Booker, D-Newark. "It's almost like you just pulled off a perfect-10 in the Olympics, and now somebody tells you, 'You have to do 100 more of the exact same thing.'"

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The swing bridge sometimes gets stuck when it opens a few times a week for barges on the Hackensack River. But at least for now, it's functional. A bigger worry lurks just a few miles up the tracks, where trains plunge into the Hudson River Tunnel to Penn Station.

That bore, also completed in 1910, is on borrowed time because of damage caused by Superstorm Sandy in 2012. Other aging structures on the railroad need to be rebuilt or replaced, including bridges, tunnels and the system that delivers power to the trains.

"We inherited a system that's way beyond its useful life," said Amtrak Chairman Anthony Coscia. "There's no other way to look at it."

If the Hudson River tunnel must be taken out of service before a new one is built, Booker said it could cost the region dearly.

"We are facing economic Armageddon if we don't get this done," he said.

Christie canceled a new tunnel under the Hudson River seven years ago and has faced criticism for that decision ever since.

That tunnel was flawed, Christie said Friday, because it would not have connected to New York Penn Station. He said he "fought hard" to make Penn Station the destination for New Jersey commuters. "Some project is not better than the right project," he said.

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Sen. Bob Menendez, D-Paramus, said Friday that "we're turning the page" by getting the $1.5 billion bridge started.

"Historically, projects like the Portal Bridge have transcended partisanship," he said.

While New Jersey leaders may be united on what's called the Gateway project, it isn't clear whether it enjoys the same level of support from the administration of President Donald Trump.

"We have a little more work to do with the White House," Christie said.

Christie, a Trump ally, is leaving office in January. If Democrat Phil Murphy wins the election next month, as many expect, he'll have to work with a Republican president who campaigned on rebuilding the country's infrastructure but so far hasn't made any major commitments.

Transportation Secretary Elaine Chao testified to a Senate committee in May that Trump understands the project's importance because he's a New Yorker.

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Christie, New York Gov. Andrew Cuomo and members of Congress from both states met with Trump last month in Washington to discuss Gateway. Some came away optimistic that the president would follow through, but Booker said he was less sure.

"The only thing that's giving me concern right now is the president of the United States," Booker said. "I'm hoping he comes through with what he indicated he would."

Future phases of the project will add capacity in Penn Station, expand the railroad to four tracks from Newark to New York, and build the "Bergen Loop" connection at Secaucus Junction to offer more North Jersey commuters a one-seat trip to New York.

The original tunnel into Penn Station will be rehabilitated once the new tunnel opens.

The entire project is currently estimated to cost $30 billion.

"The longer we wait, the more expensive it is," Booker said.

Still, he said Friday's groundbreaking was evidence that the project was moving ahead.

"Finally, we have tangible progress," he said. "It took a lot of work to get here."