With just five days left before Governor Pataki’s deadline for negotiations over ground zero, speculation is mounting that a proposed rail link to Midtown Manhattan from New Jersey will somehow figure into the final agreement between Larry Silverstein and the Port Authority.

The Port Authority, which owns ground zero and leased the twin towers to Mr. Silverstein, has a 12-person board composed of six members appointed by the governor of New York and six members appointed by the governor of New Jersey.

The Trans-Hudson Express tunnel, whose cost has been estimated at $6 billion, would add a new tunnel under the Hudson River and double New Jersey Transit’s capacity into Midtown Manhattan. The project, known as Access to the Region’s Core, would be paid for with funds from New Jersey, the federal government, and the Port Authority.

Two sources familiar with the negotiations told The New York Sun that the New Jersey faction of the Port Authority, led by its chairman, Anthony Coscia, is at odds with the New York faction, led by the authority’s executive director, Kenneth Ringler, an appointee of Mr. Pataki.

Several New Jersey officials, including Governor Corzine, have said that completing the rail link is a top priority, and some development experts suggest that increased support from New York State for the rail link could be the key to winning over Mr. Coscia to Mr. Pataki’s goal of closing a development deal for ground zero by the March 14 deadline.

Last month, at a press conference in Rockland County that garnered little attention at the time in New York newspapers, Senator Schumer pledged his support for the New Jersey rail link, and indicated that he would press the federal government for increased contributions.

“The Access to the Region’s Core project is expected to grow business and create new jobs from New York City up through the Hudson Valley. Specifically, the project will generate 2,000 new construction jobs for New Yorkers and post-construction jobs are expected to reach nearly 28,000 in New York. Overall, expected business growth from the tunnel will generate $384 million in new government revenue for New York and New Jersey,” a press release from Mr. Schumer said.

The chief planner of the rail link for New Jersey Transit, Richard Roberts, said yesterday it was the first time in his 35-year career that a New York senator has given his full support to a project that he said is “largely being driven by New Jersey.”

“New Jersey has made it 100% clear that we are not expecting New York State to contribute a thin penny, and not looking to New York City to pay for a thin penny,” Mr. Roberts said. “For New Jersey, this tunnel is the important project we would like the Port Authority to fund.”

Governor Corzine, inaugurated in January, has largely stayed out of the public fray on negotiations over the future of ground zero. A spokesman for Mr. Corzine, Brendan Gilfillan, said yesterday that the rail link remains a top priority for the governor and that he was encouraged by Senator Schumer’s support of the plan.

One week after Mr. Schumer endorsed the rail link, the senator introduced a proposal to break the stalemate at ground zero. He suggested that the Port Authority should move into the Freedom Tower in exchange for a strict timetable and concessions by Silverstein Properties.

A spokesman for the Port Authority, John McCarthy, denied yesterday that the New Jersey rail link has figured into the ground zero negotiations. He would not comment on the status of the discussions.

In May 2005, Mr. Pataki said he supported the New Jersey rail link, and he tied his decision to the Port Authority’s future support of a rail link from Lower Manhattan to John F. Kennedy International Airport.

Mr. Pataki has committed the state’s remaining $1.7 billion of Liberty Bonds to Mr. Silverstein with the condition that he strikes a deal with the Port Authority by the deadline. Negotiations are ongoing between the Port Authority and Mr. Silverstein, as well as Mr. Pataki’s downtown tsar, John Cahill.

Today, representatives of Silverstein Properties and the city will speak at a hearing before the City Council’s Lower Manhattan Redevelopment Committee.

The Bloomberg administration is not directly involved in negotiations between the Port Authority and Mr. Silverstein, who wants to rebuild 10 million square feet of office space. As a leverage point to help determine the future of the site, the city is holding back its $1.7 billion in tax-exempt Liberty Bonds from Mr. Silverstein, although it could approve them as early as March 14 – the day of Mr. Pataki’s deadline – when the board of directors of the Industrial Development Agency is scheduled to meet.

There is no indication from City Hall that it intends to give the bonds to Mr. Silverstein. The city maintains that unless a dramatic change is made to the current development plan, only two of the four planned towers would be completed and that none of Mr. Silverstein’s insurance proceeds would remain to build out the remainder of the site.

Yesterday at 7 World Trade Center, the building Mr. Silverstein has rebuilt next to ground zero, the developer said he is capable of building the four planned towers and that he plans to break ground on the Freedom Tower next month. A spokesman for Mr. Silverstein declined to comment on the negotiations.

Construction on the major components of the New Jersey rail link would not begin until 2009, with completion scheduled for 2015.