Metro’s biggest union is trying to rally support from pro-union groups and local community organizations to stop the District from privatizing some of its bus routes now run by the transit agency.

The District’s Department of Transportation is seeking a private contractor to take over about two dozen bus routes that Metro runs for the city and the popular D.C. Circulator bus system.

Operating the buses would be part of a larger deal in which a private contractor would also build and operate a streetcar system in Anacostia and along the H Street corridor.

City officials said the move is meant to create a more unified, efficient transportation system under one contract that could be worth at least $1.5 billion over 30 years.

But leaders of Amalgamated Transit Union Local 689 say that contracting out bus service to a private operator could cost about 200 Metrobus drivers their jobs, and they warn that riders could end up with fewer bus routes, if the company decides to cut back to save money.

“We must keep public transportation public,” said Local 689 President Jackie Jeter. “When you start privatizing routes, you lose your say. This is about giving the public their say.”

On Wednesday night, about 100 citizens and union members, along with labor organizers, gathered at a church in Southeast Washington to protest the city’s proposal.

Some Metrobus drivers said they are concerned that a private company would offer lower pay, fewer benefits and less-attractive pension packages for employees, which could undercut future contracts with Metro. Local 689 is expected to vote Tuesday on a new contract that gives Metro employees an 11.4 percent pay raise over the next several years.

Union leaders and Metrobus drivers said they are also concerned about how privatizing bus routes in the District would affect riders.

“We pride ourselves in the relationships we build with customers and getting them to work and other places on time,” said Keith Bullock, a bus operator out of Metro’s Southern Avenue division.

Transit experts said the District’s plan comes as the city struggles to attract a private operator to run its streetcar system. District officials made the Metro and D.C. Circulator routes part of the deal, they said, to make it more attractive. The city said it has received interest from 20 companies.

Some transit watchdogs say the District has also become frustrated with reports from Metro riders about rude drivers and late buses.

But city officials said their search for a transit contractor is solely designed to create “the most effective, user-friendly, state-of-the-art transportation system” possible, according to Ronaldo “Nick” Nicholson, a chief engineer at DDOT’s Infrastructure and Project Management Administration.

“We need to integrate our transportation systems in a way to provide for growing communities and connect those communities,” he said. “This is meant as a way to synchronize those efforts.”

Changing the city’s bus operations would mean the District would no longer pay about $32 million a year to Metro to run its roughly two dozen bus lines. It would also end a little-known relationship with Metro and the D.C. Circulator bus system, which many riders say they find easier to use and more reliable than Metrobus. The District pays Metro an administrative fee of about $700,000 annually to manage First Transit, the outside contractor that runs the D.C. Circulator. The District pays about $15 million a year to run the D.C. Circulator.

City Council member Muriel Bowser (D-Ward 4), who also sits on Metro’s board of directors, is skeptical about the city’s privatization plan. She questioned whether Metro should be pushed to improve its bus service instead of creating another deal to run bus systems.

“Why not invest in what we have rather than create a new one?” she said. “Eventually it might not be as cost effective.”

Other jurisdictions in Maryland and Virginia have privatized their local bus routes.

At Metro, General Manager Richard Sarles said that if D.C. officials want to take over the bus service Metro provides, they should.

“If they feel they can do it better, that’s their choice,” he said. “They can determine what’s best for them.”