Sen. Charles Schumer has a new pitch for a seemingly dead-in-the-water project to build a tunnel between New York and New Jersey.

A massive upgrade to Amtrak's system that includes a new two-tube tunnel under the Hudson River would be the largest infrastructure project in the U.S. and could cost as much as $25 billion, Schumer said yesterday.

He proposed financing the project, called the Gateway Program, with a nonprofit development corporation that could leverage billions from private, federal and state dollars.

The current tunnel, used by 450 trains a day, is 105 years old and deteriorating much faster than expected, Schumer said. It could be deemed structurally unsound in a few years.

If shut down without an alternative, the senator warned it could cause a national recession. "It's tantamount to economic suicide," he said.

A development corporation -- which could include New York, New Jersey, Amtrak, the Port Authority and the MTA -- would allow the project to get both federal mass transit and railroad funding -- as well as private money.

"The hardest part is piecing together the massive financing puzzle," said Schumer (D-New York).

The senator also proposed that Congress let Amtrak keep the money it makes on Northeast Corridor routes for the region, rather than use it to subsidize other long-distance routes that lose a lot of money. The feds would then cover money lost in operating other parts of the system.

Other features of the Gateway Program include connecting Penn Station's tracks and platforms with the future Moynihan Station at the Farley Post Office building.

The senator was critical of Gov. Chris Christie, who withdrew support for a project, called Access to the Region's Core, to build a new tunnel in 2010, and said Superstorm Sandy showed why building it was urgent.

"The timeline for necessary repairs was drastically accelerated and confirmed that Christie's decision to pull the plug on ARC was a massive mistake," Schumer said.

Christie was critical of the design of the project, and concerned about it going over its $8.7 billion price tag.

"It's easy for Senator Schumer to make these claims when New York wasn't contributing a dime to the ARC Project and didn't step up to take on any of the costs of the project's overruns," said his spokeswoman Nicole Sizemore in a statement.

She said Christie has made it clear that both the federal government and New York must be equally committed, and that the project be fairly funded.

Cuomo has called for the new tunnel to be funded by the federal government -- rather than through a loan.

He said he commended Schumer for making the tunnels a national priority. "We both agree that they will require significant federal investment and I look forward to working with him to move this critical project forward," Cuomo said.

Amtrak said they appreciated Schumer's support and that the development corporation is a good idea.

"Building a new tunnel under the Hudson River is of the utmost urgency to both the region and the entire Northeast Corridor," said its President Joseph Boardman in a statement.