With two exceptions, Dorchester Democrats on Beacon Hill voted against a bill overhauling the state’s transportation infrastructure. The bill is currently on the governor’s desk.

State Sen. Jack Hart and state Reps. Marty Walsh, Brian Wallace, Marie St. Fleur and Willie Mae Allen issued “No” votes on the bill, citing a lack of guarantees against fare hikes and not enough protections for union workers. Sen. Sonia Chang-Diaz and Rep. Linda Dorcena Forry signed off on the bill.

Overall, the bill passed by a 27-11 margin in the Senate and 130-25 in the House.

Chang-Diaz and Forry said the legislation streamlines a spread-out transportation bureaucracy, putting several agencies, such as the struggling Massachusetts Turnpike Authority and the debt-laden MBTA directly under control of the governor. The bill, which creates a super-agency known as the Massachusetts Department of Transportation (MassDOT), is expected to generate $6.5 billion in savings over 20 years.

“When we have an opportunity to do that, we have to do it,” Forry said.

The bill depends on $275 million drawn from a sales tax increase tucked into the fiscal 2010 budget lawmakers passed on Friday. Gov. Deval Patrick has said he will veto the tax increase unless a bill containing ethics reform reaches his desk.

Chang-Diaz defended the transportation bill, but added the $275 million is a “temporary solution.”

“I think there’s more work to be done there,” she said.

But others blasted the bill. Rep. Allen said she voted against the bill because there were no guarantees that MBTA fare hikes would not go up, as the agency, facing a $161 million deficit, has warned.

“If there was anything there to indicate they were not going to raise the fares, I would’ve thought about it more,” she said. “I just don’t think it was a very good bill, period.”

Rep. Walsh, a top labor backer in union-rich Dorchester, took to the House floor to protest the legislation, telling fellow lawmakers it steals away workers’ collective bargaining rights and doubted the expected savings.

“When I supported this bill during the debate several weeks ago, there were protections in this bill for collective bargaining,” he said. “When the bill came out today, those protections that you voted on in this chamber were taken away.”

Forry said lawmakers are working on a separate piece of legislation to correct any union-related problems.

Chang-Diaz said the dispute over whether collective bargaining rights are in the legislation is up for interpretation.

“Everybody in the Senate is committed to protecting bargaining rights,” she said.

Union officials were apoplectic over the bill. Before the vote, AFL-CIO chief Robert Haynes wrote to senators, calling for them install spots on the boards under the Department of Transportation.

“All votes relating to these matters may be considered Labor Votes and calculated into Labor Voting Records upon which endorsements and levels of support are determined,” he wrote.

Material from State House News Service was used in this report.