Waving an ivory staff as he spoke before a crowd of about 140 yesterday afternoon, a community activist from Bedford-Stuyvesant, Atiim Ferguson, vowed to wage “a war in the streets” if the Metropolitan Transportation Authority rejects the bid by the developer Bruce Ratner for the 8.4-acre rail yard in downtown Brooklyn.

According to documents released Friday by the MTA, Mr. Ratner’s firm, Forest City Ratner, is offering the transportation authority $50 million in cash for the development rights to the Vanderbilt Yards site. A rival bidder, Extell Development Company, is offering $150 million in cash for the rights. An Extell spokesman, Robert Liff, said his firm’s plan for the site would require $150 million in city and state subsidies. In February, city and state officials pledged to provide a total of $200 million in subsidies for the Ratner project, although a pro-Ratner group, Brooklyn United for Innovative Local Development, distributed fliers along Atlantic Avenue yesterday saying the Ratner plan would use only $100 million in public money. A spokeswoman for Forest City Ratner, Lupe Todd, said she could not explain the discrepancy between those two figures last night.

MTA board members will meet with the authority’s staff in closed-door sessions throughout the day today and tomorrow at the agency’s headquarters on Madison Avenue, according to an MTA spokesman, Tom Kelly. “If everyone gets their questions answered, then I assume it’s possible” the board will vote on the Vanderbilt Yards bids at a public meeting Wednesday morning, Mr. Kelly told The New York Sun. If not, he said, the board would vote on the bids at its next scheduled meeting, in September.

The MTA reserves “absolute discretion” to reject all proposals and renegotiate terms for the sale of the Vanderbilt Yards rights with the bidders. The MTA may also conduct talks with developers who did not submit bids for the site before the deadline that passed July 6, according to the request for proposals issued by the transportation authority in May.

The Ratner proposal has the backing of a long list of elected officials, including Governor Pataki and Mayor Bloomberg. Under that plan, the rail yard would become the heart of a 21-acre high-rise urban hub that would include an arena for the New Jersey Nets, a professional basketball team whose principal owner is Mr. Ratner. Under the plan, city and state officials would use their power of eminent domain to evict the roughly 20 residents and businesses on the blocks surrounding the rail yard who have declined to sell their properties to Mr. Ratner’s firm.

At yesterday’s rally, the pastor of House of the Lord Church, the Reverend Herbert Daughtry said that if the MTA chooses the Extell bid, “the privileged, gentrified group will continue to expand its base.” Mr. Ratner has pledged to reserve 3,000 units of housing at the site for low-income and middle-class residents. According to Mr. Liff, Extell’s plan – which would be considerably smaller than Mr. Ratner’s – guarantees 1,940 units of “affordable housing.”

A state assemblyman whose district includes the rail yard, Roger Green, alleged Extell would set up a “corporate colonial factory” on the Vanderbilt Yards site. The Reverend Alford Sharpton joined Messrs. Daughtry and Green yesterday in blasting Extell for its ties to the Carlyle Group, a private equity firm with ties to President George H.W. Bush. Last month, Carlyle and Extell joined to purchase a tract of land on the Upper West Side from a consortium of Hong Kong investors and developer Donald Trump for $1.76 billion. When asked yesterday if Carlyle would be a partner with Extell in the downtown Brooklyn venture, Mr. Liff declined to comment. A spokesman for Carlyle, Chris Ullman, told New York Newsday last week that his firm is not involved in the Brooklyn bid.

Mr. Green also said: “The Extell group does not have the experience to safely develop a project of this magnitude, given the fact that one of their construction sites recently incurred serious safety issues.” Earlier this month, a vacant one-story grocery store on an Upper West Side property owned by Extell collapsed onto a nearby bus stop, briefly trapping five people – including a baby girl – beneath a pile of rubble. The city’s Buildings Department issued three violations to a firm that had been hired by Extell to demolish the grocery store, Safeway Environmental Corporation.

Supporters of the Extell plan sought yesterday to refocus the debate on the difference between the two bids, arguing that Extell’s offer would do more to shore up the MTA’s shaky finances while draining less money from the city and state government treasuries.

“Let’s stop slinging mud,” a spokesman for the anti-Ratner group Develop Don’t Destroy, Daniel Goldstein, said. “The MTA is looking for cash for its system, in particular the Long Island Rail Road, and Extell is offering $100 million more.”

Traffic slowed to a crawl along Atlantic Avenue yesterday as supporters of the Ratner bid walked from Rev. Daughtry’s church to the desolate rail yard site. Mr. Ratner was nowhere to be seen at the rally, but participants expressed affection for the developer, a 60-year-old Cleveland-born Harvard graduate who served as commissioner of consumer affairs in the Koch administration. Near the back of the parade, Tatiana Rose, 3, of South Jamaica, waved a poster that read: “A dream come true: thank you, Bruce Ratner.”

Meanwhile, at the front of the procession, Rev. Sharpton marched arm in arm with Rev. Daughtry and the executive director of the New York Association of Community Organizations for Reform Now, known as Acorn, Bertha Lewis. Under an agreement signed last month by Mr. Ratner, Ms. Lewis, Rev. Daughtry, and other local leaders, the developer would set aside 35% of construction jobs at the site for minorities and 10% for women. Mr. Ratner also pledged that 30% of total construction contract dollars would go toward businesses owned by minorities and women. Those businesses would also receive a guaranteed 20% share of the contracts for food, beverages, and other concession activities at the Nets arena. Mr. Ratner’s firm would bankroll a job training initiative and finance construction of a health-care center, a child-care facility, and youth and senior citizens’ centers.

“We are big-time losers if Ratner doesn’t win,” Rev. Daughtry said yesterday.