The board of the Metropolitan Transportation Authority voted overwhelmingly yesterday to sell development rights to Bruce Ratner, who plans to build a basketball arena for the Nets and 6,000-unit development over the 8.3-acre Atlantic rail yards in Brooklyn.

The firm Forest City Ratner Companies agreed to pay $100 million for the right to develop over the rail yards – $50 million less than another bidder, the Extell Development Company, offered, and less than half the $214.5 million assessment calculated by an appraiser the MTA hired. That became a point of contention for critics and one member of the board, Mitchell Pally.

Forest City Ratner has said its bid includes $345 million in capital improvements to the rail yards. Some of that work is needed to build the platform on which the $3.5 billion development, including the arena, will stand. Mr. Pally, an attorney from Suffolk County, said those improvements were never identified as needed by the Long Island Rail Road. Mr. Pally was alone, however, in his sharp criticism of the Authority, just as he was in July in objecting to the board’s decision to negotiate exclusively with Forest City Ratner.

“Instead of buying something the Long Island Rail Road does not want, which is this project, we should take the entire $214 million in cash and use it for projects which the Long Island Rail Road does want,” he said.

“That’s not the deal that is on the table,” the MTA chairman, Peter Kalikow, said. “The only deal we have on the table that is real is the one that I’m presenting to the board.”

Mr. Pally responded, “I disagree that it’s real. It’s not real.”

Mr. Kalikow, his voice rising, said the marketplace had determined that the value of the property was lower than its appraised value.

Mr. Kalikow said the Extell bid, put together only days before the July 6 deadline and favored by those who oppose Forest City Ratner’s plan, did not adequately explain how it would build the platform, among other concerns.

The City Council member from Prospect Heights, Letitia James, vowed a legal fight, as did property owners who could lose their homes or businesses if the city invokes eminent domain. Most property owners in the area have sold their holdings to Forest City Ratner, which would own 80% of the necessary land once it closes the deal with the MTA.

Of the 28 members of the public who spoke at the meeting, a slight majority, composed of workers from the building-trades unions and residents of the relatively poor surrounding neighborhoods, favored Mr. Ratner’s proposal and legally binding agreement with the community, which promises, among other things, that at least one-third of the new housing will be “affordable.”

The controversial development, which critics say will be out of scale with the neighborhood, still faces environmental review, and the sale of development rights has yet to be approved by the state’s Public Authorities Control Board. The state and the city have pledged $200 million to the project. If all goes well for the project, construction would begin next year and the Nets would play in the arena by the 2008 season.