New MBTA general manager Luis Ramirez was greeted to his first meeting of the agency's oversight board by hundreds of his new employees chanting slogans against T managers and plans to privatize services.

The labor union representing the MBTA's bus mechanics, Local 264, used the rally outside the MassDOT offices to launch a new advertising campaign opposing the outsourcing of the system's bus maintenance garages and targeting the private companies that could be interested in taking over the work.

Local 264 business manager Mike Vartabedian says the union has offered to cut costs by $29 million dollars, but T managers are ignoring that offer and are determined to outsource the jobs to companies the state has already had disappointing contracts with.

"So we're going to go back to them? That's what we're going to do? We're going to get rid of the best mechanics in the country and gamble with the taxpayers and the safety of the riders," Vartabedian said.

In anticipation of the board voting this year on which of the nine bus garages to give over to private companies, the union is targeting some of those vendors with an ad campaign. A website and ads claim some of the interested companies have questionable track records, including under-bidding contracts and going back to taxpayers to make up the difference.

Vartabedian pointed to transit company MV Transportation, who they say admitted in court documents to underbidding a contract to run the Durham, NC bus system by over $46 million. Another company, TransDev, is owned in part by French transnational transportation firm Veolia, which was part of the group that operated the MBTA's Commuter Rail before losing the state's contract in 2014.

“It’s absurd to hear the Baker administration is strongly considering selling off core MBTA services to groups that have already failed taxpayers, riders, and workers miserably before in multiple states," Vartabedian wrote in a statement.

The rally comes a day after a Boston Globe editorial heaped praise on the MBTA and Gov. Charlie Baker's use of the exemption from an anti-privatization law to leverage contract concessions from the T's biggest labor union.

Pollack said the board has not predetermined any decision on privatization, but that there are budget savings that needs to be found by cutting back on bus maintenance spending. Those savings must be "achieved through some combination of collective bargaining, unilateral management actions and potentially using private vendors," Pollack told reporters Monday.

"All three of those are going to stay on the table until we have a strategy for meeting the budget," Pollack said.

In 2015, Democratic lawmakers granted Baker and the MBTA's board a three-year exemption to the so-called "Pacheco" law that makes the process of outsourcing difficult for state agencies.