Mayor Michelle Wu appeared outside Ashmont’s MBTA station on Thursday to promote her proposal for spending $8 million in federal funds on making three bus lines fare-free for the next two years.

Standing behind Wu on her second full day as mayor were several city councillors, including Dorchester and Mattapan Councillor Andrea Campbell, who had objected to the council taking up the proposal at its Wednesday meeting. She said she supports the proposal but more discussion was needed before the money could be appropriated.

Wu’s proposal would extend a four-month pilot for the Route 28 bus, and add the 23 and 29 buses. The 28 bus pilot, which cost $500,000 in city funds, is slated to run through the end of the year. The bus runs from Roxbury’s Nubian Square down to Mattapan Square.

Route 23, whose buses provided an occasional backdrop for Wu’s remarks as they rumbled behind her, runs from Ashmont Station to Ruggles MBTA Station in Roxbury. The 29 bus heads up Blue Hill Avenue, from Mattapan Square, to Jackson Square in Jamaica Plain.

More than 59 percent of riders on the three bus lines are low income, and more than 96 percent are commuters of color, according to Wu. “By taking this action, we truly will connect our communities and supercharge our recovery, putting these federal recovery funds to good use by supporting and investing in communities hardest hit by this pandemic,” Wu said.

A fare-free MBTA was part of Wu’s mayoral campaign platform and a plank that was often greeted with skepticism from opponents. In response, Wu often pointed to city officials in Lawrence making three bus routes fare-free in 2019.

Since the start of the fare-free pilot for the 28 bus in Boston, the route has seen the highest ridership levels in the system. “Bostonians have already voted with their feet to show what works,” Wu said. “Expanding this program to include the 23 and the 29, and extending it from four months to 24 months, is an important first step in Boston’s journey towards a brighter, more reliable transit future.”

Asked what happens to the pilot once the federal funding ends, Wu said Boston will look to the State House for partnerships to keep it going. “The goal is to very carefully invest in outreach, ensure that we are measuring and connecting with residents on the ground, and be able to present the results of that, show the numbers, show the proof that this works to be able to then say we need the investment and the return on investment at a much broader scale,” she said.

Wu said city officials picked the three routes because they are entirely in Boston, allowing them to more quickly coordinate the pilot.

Her fare-free initiative came up in Wu’s meeting with Gov. Charlie Baker at the State House on Wednesday. “We also talked not just about fare accessibility but reliability as well, and the need for Boston to move quickly on dedicated bus lanes throughout the city,” she told reporters. “So he pledged continued support to ensure the city has what we need to move more quickly on that front. There will be much more work ahead with the state but it was a good foundation, a good starting point with the governor.”

Wu publicly announced the proposal on Wednesday after her hour-long meeting with Baker.

City Councillor At-Large Michael Flaherty, who chairs the council committee focused on Covid recovery, said Wu approached him about the proposal earlier this week.

When asked about a free MBTA two months ago, Flaherty had answered with a question: “Is it realistic for us to think the T can be free?” After Wu’s press conference at Ashmont on Thursday, Flaherty said he was “on board right away” after Wu approached him. Citing the impact the three fare-free bus lines would have on families in Dorchester, Mattapan and Roxbury, Flaherty said, “Those neighborhoods were some of the hardest hit by the pandemic” and would benefit from the proposal.

Campbell, who objected to the proposal at Wednesday’s council meeting, said she was pushing for a hearing to allow residents an opportunity to weigh in. “We know it works to help people who desperately need it,” she said after Wu’s press conference.

Joining Wu, Flaherty and Campbell at Ashmont MBTA station were several local lawmakers, including state Reps. Liz Miranda, Brandy Fluker Oakley and Nika Elugardo. Matt O’Malley, who represents Jamaica Plain and West Roxbury on the City Council, as well as At-Large Councillor-elect Erin Murphy also stood behind Wu.

The proposal is expected to again come before councillors on Wednesday, Dec. 1.

“This will pass the council,” O’Malley said.