Developer Edens is expanding Boston’s South Bay center with new retail space, 475 apartments, a hotel and 12-screen AMC Theatre.

Fairmount Line passengers will have access to eight more trips per weekday and will be able to tap CharlieCards to board core stations starting this spring under a new pilot program.

The $1.2 million program will run four more passenger trains in each direction every day on the line through parts of Dorchester, Mattapan and Roxbury. As part of the pilot, the T will also install fare validators on platforms at Zone 1A stations along the Fairmount Line, an initial step toward long-term plans to implement paperless boarding across the entire commuter rail system.

Activists and local officials have long pushed for the MBTA to operate the Fairmount Line at a cost and frequency similar to the T’s subway network. It is the only rail line accessible to several Boston neighborhoods with significant black and Latino populations.

The line also includes a stop at next to the South Bay Center, where a major expansion of the shopping center and a pair of proposed multifamily developments could seeing the addition of around 1,000 apartments on the site.

The pilot program that the Fiscal and Management Control Board unanimously approved at its meeting Monday moves closer to that model for at least the next year, after which MBTA officials will need to decide whether to make the changes permanent.

“We see this as a first step to completing the process,” said Marvin Martin, a longtime activist who said he had been involved in early discussions about expanding service into a so-called “Indigo Line.” “This process in my mind has never been completed.”

Four more Fairmount Line trips will run in each direction on weekdays starting on May 18, including a new first train of the day inbound that departs Readville at 5:10 a.m. and a new final outbound train of the night that leaves South Station at midnight.

Several of those trips will use empty trains currently traveling along the line at those times, officials said.

MBTA officials estimate the increased service and accessibility could lead to about 400 new trips per day on a line that averages 2,600. They said the pilot will need to achieve at least 185 new daily trips to ensure the per-passenger subsidy lines up with existing standards.

The pilot will allow Fairmount passengers to tap a monthly LinkPass CharlieCard or tap a card with stored value to pay the $2.40 fare for Zone 1A trips. They would then receive a printed receipt that conductors will accept onboard.

Commuters traveling between South Station and Newmarket, Uphams Corner, Four Corners/Geneva, Talbot Avenue, Morton Street, Blue Hill Avenue, or Fairmount can make bus transfers on the same ticket, but they will not be able to use the same tap to transfer between commuter rail and one of the T’s four subway lines unless they have a LinkPass.

The FMCB in November adopted several resolutions calling for a new office to oversee a transformation of the commuter rail network into a mostly electrified system with 15-minute headways between trains at key stations.

One of those resolutions called for electrified pilots in the near future on the Fairmount Line, the Providence/Stoughton Line, and a part of the Newburyport/Rockport Line.