Rep. Barbara Comstock (R-Va.) on Thursday renewed her push to extend federal funding for Metro, although she scaled back legislation she proposed last year to reduce its cost in hope of winning quick passage.

Comstock’s revised bill would continue federal funding for Metro for 10 years at its current level of $150 million a year; the original version, proposed in December 2017, increased funding 50 percent to $225 million a year.

The revised legislation also drops a provision replacing the 16-member Metro board with a temporary five-member reform board with special powers to unilaterally revise union agreements and contracts with suppliers.

Despite the changes, prospects for the legislation remain uncertain. None of the Democrats who dominate the region’s congressional delegation have supported it, mainly because it includes measures to roll back union benefits and protections. Comstock’s office said the earliest it might be considered would be in a lame-duck session after the midterm elections in November.

Rep. Gerald E. Connolly (D-Va.) derided Comstock’s action as a “last-minute, desperate” effort to win political support in a tough reelection battle. He noted that Comstock filed the revised legislation on the eve of her first campaign debate against her Democratic challenger, state Sen. Jennifer T. Wexton (Loudoun).

Still, Comstock’s effort underlined the importance for Metro and the Washington region of persuading Congress to extend a program that has provided the transit agency with critical money for capital spending, such as buying new rail cars and other equipment.

The federal program is scheduled to expire next year after 10 years. Winning an extension is the next big financial challenge for Metro after Virginia, Maryland and the District reached a historic deal in the spring to provide the agency an additional $500 million a year in dedicated funding for capital needs.

“It is critical we not lose sight of the remaining effort before us and not let the system backslide,” Comstock said in a statement.

The annual federal grant must be matched by the District, Maryland and Virginia, each of which contributes a third of the total.

Comstock — whose district includes Loudoun County, and parts of Fairfax and Prince William counties, among other jurisdictions — is the only Republican in Congress representing a jurisdiction served by Metro.

As such, her original bill was seen as having a better chance than several proposed by the region’s Democrats given that Republicans control both houses of Congress.

But her initial bill did not receive a hearing. She has made changes in hope of winning approval before the funding expires.

“Given the complexity of this issue and time moving quickly on this, we’re trying to get this to be a little bit simpler, and to build on what the jurisdictions have done at this point,” Comstock’s deputy chief of staff Jeff Marschner said.

As before, her bill provides less-generous pension benefits — under a 401K-style, defined contributions plan — for future Metro hires. It also would amend a federal law, known as the Wolf Act, to strengthen management’s hand in mandatory binding arbitration of labor contracts.

Last month, in a financial hit for the cash-strapped agency, an arbitration board said Metro must provide $82 million in wage increases to thousands of workers by summer 2020. The arbitrators also rejected management’s proposal to switch future hires to the kind of pension plan that Comstock supports.

Metro welcomed Comstock’s action and endorsed her call for pension changes.

“We thank Congresswoman Comstock for her work to reauthorize PRIIA funding, which is critical to Metro’s ability to invest in safety and reliability improvements for our customers,” Metro spokesman Dan Stessel said, using the acronym for the federal Passenger Rail Investment and Improvement Act.

“This bill also recognizes the importance of Metro’s long-term financial health through pension reform for new employees, while meeting our commitment to existing employees,” Stessel said.

Connolly said Comstock’s bill “is to me, candidly, an attack on unions and an attack on employee benefits, described as reform.” He added: “It has no support in the national capital delegation and it will not pass this Congress. . . . It’s a last-minute, desperate attempt before a debate to try to persuade her voters she’s doing something.”

Marschner denied that, saying, “We’re not doing this because of politics. . . . We need to get PRIIA funded.”

He added that Comstock has been a consistent advocate for Metro. “Her record is clear. She’s fought hard for Metro funding year after year. We have a good working relationship with [Metro.]. And we’re working with the Federal City Council and outside entities to improve [Metro],” he said.

Wexton spokesman Ray Rieling declined to comment on Comstock’s bill, saying the state senator had not had time to review it.

Wexton has supported extending federal funding for Metro for capital expenditures. Like Connolly, she also proposes creation of a new program to provide federal funding for Metro’s operating costs.