Standard & Poor's Corp. said it will curb the Massachusetts Port Authority's role in state projects, including double-stack rail development.

The Wall Street bond rating agency's reaction followed a "get-acquainted" meeting last week with Massport's new executive director, Stephen P. Tocco, and other officials of the authority's new Republican administration.Ernest Perez, a vice president of S&P's Ratings Group, said that while S&P officials came away from the meeting "with a good feeling," they also made it clear that Massport funds may not be used for state programs without rating consequences.

Bond analysts have voiced concern that close ties between Republican Gov. William F. Weld and Mr. Tocco, a former chief economic aide to the governor, could lead to a greater Massport financial role in state initiatives that fail to pass the Democratic Legislature.

Massport is an independently financed authority that issues its own bonds.

Speculation has focused on possible Massport backing for Gov. Weld's plan to raise bridge clearances for double-stack development to the ports of Boston and New Bedford.

The $200 million plan to use state bond funds faces uncertainty in the Legislature. But the use of Massport funds now seems an unlikely alternative.

Asked about the funding option, Mr. Perez said: "We made it clear that it would have a rating impact."

Massport's proposed involvement in building a "megaplex" convention center and domed football stadium for the New England Patriots football team also has sparked interest. Mr. Perez said S&P was assured that any Massport role would not be financial.

Mr. Tocco said in an interview that Massport may help to coordinate planning for both projects but that the use of Massport funds "certainly isn't on my plate."

S&P also received assurances on other issues left over from Massport's previous Democratic administration.

On growth in central administration costs, which rose 49 percent over the last three years, S&P was told that a number of unspecified expenditures had been added to the accounting category and that the entire process was under review.

Charges for central administration are assessed to the seaport and other Massport departments in addition to their own expenses.

In fiscal 1992, Massport charged $36.8 million to its departments against total net revenue of $203.8 million and earnings of $10.7 million. The seaport was assessed for $5.1 million, contributing to a $1.6 million operating loss at the port.

Mr. Perez said officials are working to correct the accounting "by this year."

Mr. Tocco also said he plans to put greater emphasis on auditing as part of his planned overhaul at the authority.

On the subject of Massport's liability for environmental cleanup from leaked fuel at Logan International Airport, Mr. Perez said the authority plans to recover costs from the owners of old fuel tanks, including Trans World Airlines.

Jerry Cosley, a TWA spokesman, said he was "not aware" of any cost- recovery efforts concerning the contamination but added, "we'll try to deal responsibly with Massport."

TWA's plan to emerge from Chapter 11 bankruptcy received court confirmation in August but has not been completed.