A conflicted Metro board committee voted Thursday to advance a proposal that would shorten service hours for two years — a controversial decision that Jack Evans, the Metro board’s chairman, said would almost certainly get a veto from the District.

The proposal will go to the full Metro board for a final vote in two weeks.

The 3-to-1 vote came after two hours of debate, in which the board members battled over the proposal’s potential impact on low-income and minority riders. Others argued that resistance to the changes, which Metro says it needs to give workers more time for much-needed track work and maintenance, would undercut Metro General Manager Paul J. Wiedefeld and system safety.

The plan would shutter the system at 11:30 p.m. Mondays through Thursdays, 1 a.m. Fridays and Saturdays, and 11 p.m. Sundays. The system would open at 8 a.m. on Sundays — one hour later than it does now. The changes, which would take effect in July after the end of SafeTrack, are intended to give workers an additional eight hours a week for track repairs and preventive maintenance.

Although the proposal has been under discussion since July, board members bandied about a range of amendments Thursday that delved into the details of how to implement the plan: Should they approve eight hours of service cuts or limit it to four? If they approve the service cuts, should they place a sunset clause on the schedule changes, meaning they would automatically revert to extended late-night hours at some point? And, if there is a sunset clause, should it be one year or two?

Evans advocated for an automatic one-year sunset, saying that the D.C. Council and Mayor Muriel E. Bowser (D) had made it clear that they have no intention of supporting any late-night service cuts that extend past summer 2018. After the vote, Evans said he would go back to them to see if they would agree to support the two-year sunset, although later that afternoon, Bowser seemed unlikely to shift her stance.

“The Mayor’s position has not changed,” said Bowser spokeswoman LaToya Foster.

During the meeting, Evans bristled at suggestions that the District was being intransigent by refusing to support the two-year plan.

“The District did compromise. The District didn’t want to do any of this,” said Evans, who is also a D.C. Council member. He said that Bowser and the D.C. Council had made it clear that they expected him to veto any cuts that lasted longer than a year. “It’s not a threat.”

“Of course it’s a threat,” said board member Michael Goldman, chairman of the panel’s finance committee.

“We believe we have compromised enormously,” Evans continued. “The board can do what it wants to do. I’ve made my decision clear, on behalf of the District of Columbia.”

The contentious meeting was emblematic of a more long-term evolution of the Metro board, which for years has been criticized for blindly agreeing to Metro management’s requests and for marching in lockstep with one another.

Thursday’s meeting was very different: Members were visibly angry and exasperated as they sparred over different proposals and angled to block one another’s amendments.

Evans argued that it was the board’s responsibility to start taking a more hands-on approach with Metro — and that reassessing the late-night service cuts on a year-by-year basis would be an important method of keeping tabs on Metro’s adherence to its safety plan.

But after the meeting, Wiedefeld said it would be irresponsible to consider ending the expanded track-maintenance schedule after just one year.

“There’s no way we’re going to have this preventive maintenance program up and running and get real data back in a year. It’s just not realistic,” he said.

Other board members raised concerns about whether the cuts would pass legal muster. An equity analysis showed that the schedule changes would have a disproportionately adverse impact on low-income and minority riders. But Metro officials said they had received general guidance from the Federal Transit Administration that the proposal would comply with Title VI of the U.S. Civil Rights Act because, across all demographics, the largest number of respondents to a Metro survey on its proposals said they preferred this plan to the other alternatives offered.

“I think we’re really on thin ice. I want to know how bulletproof we’re going to be when we get sued,” said board member Tom Bulger, who also represents the District.

Board member Malcolm Augustine, who represents Prince George’s County, said he was “very uncomfortable” with the data showing the impact the cuts would have on low-income and minority riders.

“It is very clear from this that portions of the [proposed schedule change] do not meet the standard — not even close,” Augustine said. “We would be creating some jeopardy for ourselves if we move forward with these hours in the way that they are presented.”

Augustine offered an amendment that would have provided four extra hours of track access a week, rather than eight hours, but it was voted down.

As several board members made eleventh-hour entreaties to reconsider the plan or place a one-year sunset on the schedule changes, others worried that those requests were undercutting Wiedefeld.

“We’ve heard from management that they need more time because of decisions in the past where maintenance was deferred,” said board member Robert Lauby, who is chief safety officer at the Federal Railroad Administration. “The longer we put it off, the bigger the problem gets. I think we need to bite the bullet here and make a decision.”

Goldman added in his support for Wiedefeld’s plan: “I’m not going to undercut him, and I’m not going to second-guess him.”

After the meeting, Christian Dorsey, who represents Virginia on the board, urged D.C. board members against a jurisdictional veto.

“I think that would be a huge mistake on their part,” Dorsey said. “I understand the political reality . . . The District doesn’t just want to appear as if they’re just rolling over as hours are reduced. But it would set a dangerous precedent for the troubled Metro. We don’t want SafeTrack surges to be the normal for Metro. We don’t want to be in such a state of disrepair that we even jeopardize closing at 1 a.m.”

In another example of continuing conflicts between the District and the suburbs, the city and Maryland clashed over the agency’s operating budget for the next fiscal year during the board’s finance committee meeting.

Goldman, who represents Maryland, urged reducing the increase in subsidies from his state, the District and Virginia from a total of $130 million — as proposed by Wiedefeld — by at least $30 million. To do so, Goldman called for using capital funds, instead of operating money, for some preventive maintenance and spare-parts purchases.

But Evans said the three jurisdictions should keep their subsidies at the proposed level, or even increase them. He also reaffirmed the District’s opposition to proposed fare increases and rail-service cuts.

“If anything, we support increasing the ask,” Evans said.

Board member Corbett A. Price, who also represents the District, reaffirmed his controversial proposal from earlier this week that Metro consider canceling the Silver Line extension to save money if Virginia is unwilling to support a regionwide sales tax or other dedicated funding source for Metro.

Price reiterated his suggestion during the board’s closed-door, lunchtime session, where he said the response was “stunned.”

Price’s idea, which was endorsed by Evans, drew harsh criticism Wednesday from Virginia officials, led by Gov. Terry McAuliffe (D).

Dorsey said after the closed session, “There was a general feeling it was not very helpful in terms of getting buy-in from the Commonwealth of Virginia.”

Robert McCartney contributed to this report.