Amtrak officials on Wednesday provided the most detailed public account yet for the projected costs of building a new Hudson River rail tunnel and improving other critical parts of the rail infrastructure in the New York region.
The project, known as the Gateway program, has been championed by Anthony Foxx, the federal transportation secretary, who on Wednesday visited the deteriorating rail tunnel that runs between New York and New Jersey.
In a presentation to Mr. Foxx, Amtrak officials said the entire project could cost as much as $23.9 billion, with the largest share of about $7.7 billion going toward building the new Hudson tunnel and repairing the existing tunnel. The project includes a host of other elements, including expanding Pennsylvania Station in Manhattan at an estimated cost of $5.9 billion, and replacing rail bridges in New Jersey.
The project gained momentum last year after Mr. Foxx raised concerns about the existing century-old tunnel, which has two tubes and needs repairs because of damage from Hurricane Sandy. After a contentious debate over how to pay for the tunnel project, federal and state officials agreed to split the costs and to create a corporation within the Port Authority of New York and New Jersey to oversee the plans.
After Mr. Foxx toured the tunnel on Wednesday, he said he would continue to advance the plans during the final year of the Obama administration.
“I’d like to have a financing package that is solid enough by the time we walk out of the door that everyone has the certainty that the project will happen, and the funding set aside to get it done,” he said.
Seated at the front of a special train car with panoramic windows, Mr. Foxx examined the tunnel’s crumbling bench walls and the line where floodwaters rose during the storm. A top Amtrak official, Stephen Gardner, stood nearby outlining the scope of the Gateway program and rough estimates for the cost and timeline for the plans.
Amtrak officials have been reluctant to provide specific figures for the cost of the project while they are still in the early stages of planning. On Wednesday, they cautioned that the numbers were preliminary estimates, and the real costs would be determined after conducting engineering work and an environmental plan and considering available financing.
The expansion of Penn Station, by adding tracks to the south, could start in 2024 and be completed by 2030, according to the presentation. Work to replace the Portal Bridge in New Jersey, an old swing bridge that often causes delays, could start next year. There was no timeline provided for the Hudson tunnel project, but Amtrak officials have said that work could take about a decade.
On Wednesday, when Mr. Foxx asked whether the existing tunnel was safe, Amtrak officials said that it was structurally safe, but that service was becoming less reliable. Amtrak’s chairman, Anthony Coscia, and its chief executive, Joseph Boardman, attended the tour, along with Sarah Feinberg, the head of the Federal Railroad Administration.
After a series of bad train delays at the Hudson tunnel last summer, Mr. Foxx helped jump-start long-stalled plans to build a new tunnel under the river. Gov. Chris Christie of New Jersey, a Republican who is running for president, canceled an earlier tunnel project in 2010.
This month, Gov. Andrew M. Cuomo of New York, a Democrat, announced a new effort to renovate Penn Station and to turn the James A. Farley Post Office across the street into a train station and waiting room. But questions remain over how to pay for that project’s $3 billion cost and the governor’s other transportation proposals for the region.
After the tour, Mr. Foxx praised Mr. Cuomo’s big infrastructure plans for the state, but he said officials must remain “laser-focused on fixing what is broken under the Hudson River.”