A federal agency has given a preliminary thumbs up to MARTA’s plans to build a bus rapid transit line along Campbellton Road in Southwest Atlanta.

The Federal Transit Administration recently accepted the project into its Small Starts program, which is designed for transit projects that cost less than $400 million. Though the decision is no guarantee of federal funding, it’s a crucial first step.

The Campbellton Road project is part of MARTA’s Atlanta expansion plan, made possible when city voters approved a new half-penny transit sales tax in 2016. Other major projects include the Summerhill bus rapid transit line, an Atlanta streetcar extension to Ponce City Market and the Clifton Corridor transit line from Lindbergh station to the Emory University area.

MARTA originally planned to build light rail along six miles of Campbellton Road. But after studying the route for two years, it proposed rapid buses instead. MARTA said a rapid bus line would be less expensive and disruptive than light rail but would move passengers almost as quickly.

Bus rapid transit is designed to mimic rail lines. Passengers board at stations, pay before they board and receive real-time information about arrivals and departures. The buses operate mostly in exclusive lanes to keep passengers moving.

MARTA is seeking federal funding for the $308 million Campbellton project. Exactly how much has not been determined, but under the Small Starts program the funding request must be less than $150 million.

Last month the Federal Transit Administration accepted the Campbellton line into the Small Starts program. That means the “the details we submitted are credible and they’re committed to working with us,” said Colleen Kiernan, MARTA’s senior director of government and community affairs.

The FTA will review the proposal in detail and rate it for possible federal funding. If all goes well, the FTA will approve funding for the Campbellton Road line. Kiernan said the process could take a couple years.

“There are a few milestones along the way,” she said. “This is the first one.”

MARTA says the Campbellton transit line will open in 2028.

It’s not the only MARTA project under consideration for federal funding. Earlier this year the FTA accepted the Clayton County Southlake bus rapid transit line into its Small Starts program. That project is expected to open in 2026.