OAKLAND, Calif. -- State mediators will get involved in the slow-moving contract talks between BART management and union leaders who represent 2,800 employees on Friday, according to union officials.

Jean Hamilton, the president of Local 3993 of the American Federation of State, County and Municipal Employees, which represents about 200 middle managers, said the transit agency's three largest unions asked for mediation because they believe management "is not bargaining in good faith."

BART spokesman Linton Johnson said, "We welcome a mediator" in the talks, which began on April 1 but appear to have made little progress.

Johnson said, "Anything that helps us reach an agreement that eliminates our $250 million deficit over four years by July 1 is a good thing."

The union's current four-year contract with BART expires at midnight on June 30.

AFSCME Local 3993 and Local 1555 of the Amalgamated Transit Union, which represents about 900 train operators, station agents and power workers, both voted by huge margins on Tuesday to authorize a strike if an agreement isn't reached by then.

Members of Local 1021 of the Service Employees International Union, which represents about 1,200 mechanics, custodians, safety inspectors and clerical employees, are scheduled to participate in a strike authorization vote later today.

Hamilton said it appears that at least two state mediators will be involved in the contract talks because the unions negotiate with management separately.

She said AFSCME Local 3993 negotiates by itself at one table and ATU Local 1555 and SEIU Local 1021 bargain together at another table.

Two smaller unions also are in the midst of negotiations with BART management.

The BART Police Managers Association represents sergeants, lieutenants and commanders and the BART Police Officers Association represents rank-and-file officers.