On a drizzly Tuesday morning, four members of Dorchester’s State House delegation and a couple of transportation officials gathered under an overhang on the Four Corners/Geneva Avenue platform as a hulking commuter-rail train pulled into the station, then joined a trickle of passengers in shuffling toward the doors.

It was 8:09 a.m., and the Fairmount Line was running on time.

State Sen. Linda Dorcena Forry and state Reps. Russell Holmes, Evandro Carvalho, and Dan Cullinane were on board to get a feel for the operation of the line during the morning commute by riding from Four Corners into South Station and back. They were accompanied on board by representatives from MassDOT and Keolis, which manages the commuter rail for the MBTA, and advocates for Fairmount Line equity.

Rep. Carvalho filed a bill in January that asks for a “pilot evaluation” of the Fairmount Line as a rapid transit line a la the T’s Red Line. Aligned closely with a longtime request from advocates, Carvalho’s bill proposes a rebrand of the line as the Indigo Line, with additional cars allocated and service running every 15 minutes during peak hours and no more than every 30 minutes during off-peak hours. Commuters now wait for 45 to 60 minutes between trains.

Alda Marshall Witherspoon, a frequent Fairmount Line rider for the past six months, traveled with the group of officials on her way into the city. She commutes between Codman Square and the Park Street station on the Red Line, “so literally four blocks from my house I jump on and literally ten minutes later, I’m in downtown Boston. I mean, it’s like, incredible.”

The problem, she said, is if a rider runs a tad late and misses a train, it can be another hour before the next one comes along. “So I jump in an Uber, and an Uber takes me like 45 minutes to get downtown, so the contrast between all the modes of transportation is astounding and supremely more expensive.”

Keolis GM David Scorey, who traveled along with Keolis President Gerald Francis, noted that Fairmount Line performance was consistently around 97 percent on-time as of late, despite some significant instances of trains being repurposed and cancelled along the line last fall.

Carvalho referenced a study showing that commuting times, more than education or crime levels, is the most important factor in terms of upward mobility. About 56 percent of those living along the corridor have a high school education or less, he said, and the stretch is also home to a high proportion of children in the city.

“We know that the mobility of people to get to work is very important for the community,” Carvalho said. He described the corridor as a desert in terms of rapid transit. “In fact, the folks in this corridor do not have the ability to just jump on a T like many on the Red Line or Orange Line,” he said, “so this is, more than anything, this is about economic justice; it’s about social justice; it’s about environmental justice, as well. More importantly, though, it’s about getting people out of poverty.”

The Four Corners station is one of four that were mandated for construction as part of a settlement resolving a 2003 lawsuit against the MBTA and other state agencies for failure to comply with the Big Dig agreement funding rail projects in Dorchester, Roxbury, and Mattapan. Three stations have already been built and opened – Newmarket, Four Corners, and Talbot Avenue – with the final station at Blue Hill Avenue in Mattapan slated for construction and given a $26 million budget in the 2017-2021 MassDOT Capital Investment Plan.

“This was the culmination of a civil rights battle for our right to a ride,” said Mela Bush-Miles, of the Four Corners Action Coalition and the Fairmount Indigo Transit Coalition, as they waited for the train. “Right now we’re working to make sure this line is marketed properly, so the ridership will be evidence of the need for better transportation in this community.”

Miles took a moment as the train approached Four Corners to highlight works from resident artists that have been incorporated into the station signage.

The 9-mile line connecting South Station and Readville makes eight stops through communities with high concentrations of residents of color and lower income. Proposals for improvements, many of them in line with Carvalho’s bill, are included in the just-released Go Boston 2030 report.

Rep. Holmes, co-chair of the Go Boston initiative, is focused on ensuring the construction of the Mattapan station. “We will look at transportation equity across the city,” he said. “We believe that fundamentally, us being the ones out of the gate on this first wave of what to do about the city’s transportation will transform every planning process that we have in the city.”

Public officials are keeping an eye out for development along the corridor as improvements are made along the line. The city’s chief of economic development, John Barros, said in a phone interview on Tuesday that increasing and supporting small businesses nearby is central to the health of the line.

“Small businesses provide 170,000 of our jobs, so as a sector, they are our largest job provider,” he said.

“And they’re growing. We want to make sure they’re growing along the Fairmount Corridor and that those who live along the corridor can continue to work and benefit from it.” In that regard, Sen. Forry pointed to several dilapidated lots near the Four Corners stop that she said could be poised for re-use.

As the train moved down the line, the politicians chatted with riders about their daily commutes, about their usual pass purchases, and the upsides and downsides of having the Fairmount as their primary way to get downtown.

“I use this daily, to and from work,” said Lia Savory, who boarded at Geneva Avenue. On whether the service is reliable, she said, “on the weekends, no. On the weekdays, it’s not bad. As long as I make it to work on time, that’s fine.”

Savory said notifications on the line would make for a better experience. “A lot more notifications about whether the train’s coming on this side or that side” she said. “If it says it’s going to be four minutes long, it should be four minutes. It shouldn’t go from four minutes to fourteen.”