NEW YORK (Reuters) - New Jersey’s top state and federal officials, including Governor Phil Murphy and U.S. Senators Cory Booker and Bob Menendez, toured the deteriorating century-old rail tunnel beneath the Hudson River on Monday in an effort to convince the Trump administration to fund its replacement.

New Jersey Governor Phil Murphy arrives before placing the first legal sports bets in the State of New Jersey at Monmouth Park Sports Book by William Hill, on the opening of the first day of legal betting on sports in Oceanport, New Jersey, U.S., June 14, 2018. REUTERS/Mike Segar

The twin North River Tunnels, which were heavily damaged by flooding during 2012’s Superstorm Sandy, carry hundreds of thousands of commuters a day into Penn Station in Manhattan from New Jersey. At peak hours, up to 24 trains pass through the single-track tubes every hour.

Amtrak’s proposed “Gateway” project would build a new $13 billion tunnel, doubling the number of tracks from two to four and permitting the rail agency to close down the existing tunnels one at a time for critical repairs. Officials have warned that the damage will eventually force their hand, shutting down one tube and wreaking havoc along the busiest rail line in the country.

The Northeast Corridor, which runs from Washington, D.C., through New York to Boston, carries more than 800,000 passengers a day, including Amtrak and commuter rails like NJ Transit.

As Murphy and congressional officials looked through floor-to-ceiling windows on a special Amtrak observation car, Stephen Gardner, an Amtrak senior official, described how saltwater has eaten away at the tunnel’s concrete walls and power cables.

Afterwards, Murphy told reporters that seeing the corrosion up close was “pretty alarming, to say the least.”

“This is existential,” he said, noting that the Northeast Corridor accounts for one-fifth of the nation’s economic output. “I plead with the federal government to step up and do its share.”

The federal Department of Transportation, which would have to approve the final project, did not immediately respond to a request for comment.

Both New Jersey and New York have allocated billions of dollars toward the Gateway project, but U.S. President Donald Trump has resisted providing federal funding, despite his campaign pledge to boost infrastructure spending.

New York Governor Andrew Cuomo met with Trump to discuss the project in November but came away without a deal.

Coupled with a planned expansion of Penn Station, the new tunnels could double the number of rush-hour trains, officials said, easing chronic delays exacerbated by aging infrastructure.

Booker, a Democrat considering running for president next year, likened the ailing tunnels to a clogged artery that will cause a heart attack if left unrepaired.

“Anybody who’s faced the massive delays that we see on a regular basis knows this is undermining the quality of life for millions and millions of folks,” he said.