n overhaul of the shattered tangle of subway and commuter trains in Lower Manhattan could cost more than $7 billion, four times the amount currently allocated for downtown transportation improvements, a group of high-level New Yorkers told Congress this week.

The New York officials went to Washington on Thursday to try to convince skeptical legislators that properly rebuilding Lower Manhattan's transportation system will require much more than simply repairing what was destroyed. It was the first time that the city and state have delivered a definitive list of their transit plans, with price tags and priorities attached.

Elements of the ambitious proposal, outlined to House and Senate staff members helping to plan appropriations of President Bush's $21.5 billion pledge to New York, include a relocated PATH commuter train terminal, a new subway hub at Fulton Street, a redesigned South Ferry terminal and multiple links between subways, ferries and buses.

The message was this: rebuilding the wounded center of Lower Manhattan must begin with the transit system, not only to allow New Yorkers to travel to and through downtown to their offices and homes, but also to accommodate the millions of visitors who are certain to flock each year to the memorial to victims of the World Trade Center disaster.

The New York officials, including Peter S. Kalikow, chairman of the Metropolitan Transportation Authority, Joseph J. Seymour, executive director of the Port Authority of New York and New Jersey, and Louis R. Tomson, president of the Lower Manhattan Development Corporation, admit that they are facing an uphill fight. The $7.3 billion request is four times the $1.8 billion that President Bush proposed for transportation repairs last month when he raised the federal government's total pledge to New York to $21.5 billion, from the $20 billion promised in the days immediately after Sept. 11. But the New York officials insist that they do not need that total pool of money to be increased. Rather, they would like to have money earmarked for disaster cleanup reallocated to rebuilding projects, specifically ones involving transportation.

The transportation plans could create an uncomfortable situation for the Lower Manhattan Development Corporation, which is overseeing the rebuilding process. Just days after it issued a blueprint for rebuilding the city that promised "an open and inclusive public process," city and state officials privately put together a detailed transportation plan, parts of which are likely to face opposition.

Delegation members and others in Washington said they believed Congress would look favorably on the plans. "It has to be shown clearly that the funding is for projects with a direct relationship to what happened Sept. 11," said Representative James T. Walsh, the Republican congressman who represents Syracuse and nearby areas and is the ranking New York member of the House Appropriations Committee, "but I think there is pretty broad support" to allow money previously earmarked for other uses to go to transportation.

Despite those signs, participants in the process acknowledge that the legislative process is unpredictable, and recalled New York's previous problems in promoting its needs after the attack. While Mr. Kalikow said he was "very encouraged" by the meeting, Senator Charles E. Schumer was more cautious. "I wouldn't say it's a done deal, but we have a good chance," he said.

At issue is how to allocate $5.5 billion that President Bush outlined in a March 7 ceremony at the White House. Included in the proposal, which is part of the president's $21.5 billion pledge, was $2.75 billion in disaster relief to be paid through the Federal Emergency Management Agency, which has overseen the cleanup of the site; $1.8 billion to repair, replace and upgrade the subway and PATH lines that were destroyed; $750 million to rebuild infrastructure, probably Con Edison and Verizon facilities; and about $170 million to repair roads like the West Side Highway.

The $1.8 billion set aside for transportation is barely enough to rebuild the PATH, whose station under the trade center was destroyed, city and state officials said. More is needed to repair the subway, and much, much more would be required to modernize the haphazard array of subway lines and underground connections underneath the financial district. The Port Authority and the Metropolitan Transportation Authority are receiving some insurance money, but it is being used to rebuild only what was damaged, such as the 1 and the 9 lines' tunnel, and not to pay for new projects.

New York officials want Congress to let them use money previously allocated to the Federal Emergency Management Agency or for community development block grants to rebuild and improve transportation.

At the top of the new project list is $2 billion to build what officials call a downtown Grand Central near Church Street, adjacent to the former World Trade Center site. The station would connect PATH trains with three subway lines and would include a $500 million underground concourse, stretching from near the ferry docks on the Hudson River beneath the World Financial Center and through the PATH terminal.

The passageway, which would include moving walkways, would also extend east to a new Fulton Street transit center, a newly designed, $750 million hub. The transit center would straighten out the dispiriting array of pedestrian tunnels that now connect the major subway lines in the area of Broadway, Nassau and Fulton streets; together with the PATH terminal, commuters would have a single complex linking the A, C, E, J, M, Z, N, R, 1, 2, 3, 4, 5 and 9 lines.

The plan also includes $200 million to study the possibility of an eventual Long Island Rail Road or Metro-North connection to the Lower Manhattan terminals, which would bring suburban commuter lines to the tip of the island. While many transportation officials consider such a connection unlikely in the near term, a consensus has emerged that preparing for the long-term possibility might be worthwhile.

At the southern tip of Manhattan, a $400 million terminal would replace the South Ferry subway station with a new station with four tracks and three platforms that would, for the first time, allow all 10 cars of a train to fit into the station. The terminal would also be linked to the ferry terminals at the Battery. The plans also call for connecting the Rector Street stations on the 1 and 9 and N and R lines, which are very close together but have never been linked. The $80 million Rector connector, as officials call it, would allow ferry riders who come into the South Ferry station to have another option for transferring to lines to Brooklyn.

Also proposed are $500 million for a new bus terminal near the planned memorial, to handle the heavy tourist traffic that is expected downtown. A proposal to move West Street underground, which would provide more surface area for a memorial as well as provide for better pedestrian connections between Battery Park City and the rest of Lower Manhattan, would cost up to $2 billion. Finally, transit officials have said that they plan significant security improvements, and have allocated up to $1.4 billion for those efforts.

Construction has already begun on a temporary PATH station and on the restoration of the tunnel for the 1 and 9 subway lines, both of them on the site of the World Trade Center, a development that has angered relatives of some victims. Charles A. Gargano, vice chairman of the Port Authority, said any new transit construction in the trade center area must await a decision on where the memorial or new buildings would be placed. That could mean that PATH terminal construction might not begin for five years, he said.

The Lower Manhattan Development Corporation could also find itself bedeviled by the new list of transportation proposals. While it has gone to great lengths to seek input from advisory committees and civic groups, the new list of projects appears to have emerged from the stereotypical smoke-filled room.

Mr. Tomson, president of the group overseeing the downtown redevelopment, noted that all the projects on the list presented to Congress are in the development corporation's blueprint, released last week.