Metro riders inconvenienced by a two-week partial shutdown on the Red Line probably didn't give much thought to the branding of the bus shuttles carrying them on their plodding ride between the Silver Spring and Fort Totten stations.

But those buses — private coaches with drivers hailing from out-of-state — could be a sign of things to come at Metro: more privatization, with a focus on outsourcing bus service.

It's a shift that's been forecast by Metro General Manager Paul J. Wiedefeld, and cheered by politicians and Metro board members who see it as an opportunity to save on costs.

The transit agency recently announced that it is seeking proposals from outside contractors interested in handling bus operations and maintenance at Metro's new Cinder Bed Road bus garage in Newington, Va. The contract would hand over the operation of 17 bus routes to a private company, and that company would be responsible for providing an estimated 129,599 hours of service to passengers each year.

Metro board member Michael Goldman, chairman of the panel's finance committee, agreed that the potential outsourcing at the new bus garage could be a first step toward more privatization — and that's a good thing, he said.

"If the general manager is going to stick to his goal of limiting cost increases, it's these kids of advances or changes that he's going to have to have the ability to take advantage of," Goldman said.

A quiet step in that direction came this month, as private coaches shuttled thousands of passengers along the four-mile stretch of the Red Line that was to be shut down through Sunday for track maintenance. Metro is paying Academy Bus $739,000 for 40 coaches. That's an average of $18,475 per bus, funded by the agency's capital budget.

"This includes all necessary staffing with professional drivers, in addition to the provision of buses to provide the service, fuel, and other expenses," Metro spokeswoman Sherri Ly said.

Ly said Metro hired the private coaches "so as not to impact regular bus service for the 400,000 customers who depend on Metrobus." Officials say the agency is functioning with bare-bones levels of staffing after Wiedefeld cut hundreds of jobs last year. And a fleet of 105 buses was temporarily taken out of service to investigate a suspected mechanical defect.

The agency said it could not calculate how much it would have cost to provide the same service using Metro workers and buses because it would include a variety of costs such as overtime and fuel, making a breakdown difficult.

When asked whether Metro would use private contractors to provide bus shuttles during the agency's next planned extended maintenance shutdown, scheduled for the Yellow Line in May, Ly did not rule it out.

"It is entirely possible," she said.

Other transit agencies have taken Metro's approach, opting for private coaches to provide shuttle service during track maintenance. In Boston, for example, the Massachusetts Bay Transportation Authority started using Peter Pan Bus Lines last summer to provide service during bouts of track maintenance work.

"We just don't have the in-house capacity to provide all those bus shuttles," MBTA spokesman Joe Pesaturo said. "That's why we sometimes contract out.

Bus operators and union officials criticized Metro's decision, saying it spent more than necessary by outsourcing the service. They also say riders' needs weren't met, noting that the private coaches can't accommodate bikes or people with disabilities, and they said the drivers worked far longer hours than those allowed for Metro's own operators.

But they also fear what the Red Line shuttles portend for the future — and their jobs.

Wiedefeld has proposed other ideas for potential outsourcing, including track maintenance and station operations on the second phase of the Silver Line. He has suggested opportunities to privatize jobs that are peripheral to Metro's central mission, such as handling the cash and coins that come in and out of the system, or managing the warehouses where spare parts for trains and buses are kept.

Thursday morning, Metro's largest union held a protest outside the Cinder Bed Road facility as agency officials held a scheduled meeting with potential vendors interested in submitting bids for the bus garage contract. At one point, union members poured into the street, blocking the cars entering the bus garage as they chanted "Your job is next."

Anthony Garland, international representative of Amalgamated Transit Union Local 689, cited problems that have plagued the privately operated D.C. Circulator and MetroAccess paratransit service as examples of how private companies scrimp on vehicle maintenance and provide subpar service.

"You don't have to leave this city or this region to understand that privatizing public transit does not work," Garland said. "People will run this system down, make the money they can, and when it runs down, they'll leave and go somewhere else."

But Goldman said the Cinder Bed Road facility is the perfect opportunity to test outsourcing because it would not require eliminating any current Metro workers.

The union's concerns aren't getting much traction among other Metro board members either.

"Why does anyone think the status quo works, or should be perpetuated?" said board member David Horner, who represents the federal government.

Horner said Metro has the capability to establish agreements with private bus providers and operators that are cost-efficient and include adequate regulations and safeguards.

"Across the country, agencies responsible for running infrastructure have quickly acquired the know-how to negotiate and enforce agreements with infrastructure developers and operators to protect the public interest," Horner said. "These arrangements generally result in greater transparency and heightened accountability to the public."