Commuters arrive on Capitol Hill using Washington's Metro system. (J. Scott Applewhite/AP)

A dozen House and Senate Democrats representing the Washington metropolitan area asked the Government Accountability Office on Thursday to produce a report on how Metro is run and funded.

They said the study should consider safety, long-term funding options, the makeup of the Washington Metropolitan Area Transit Authority board, capital improvements and compensation for the unionized workforce.

“Previous GAO reports have lent insight into these issues, but we believe a comprehensive analysis would be worthwhile in providing an objective picture of where WMATA is on these fronts and where it should be going in the future,” the members wrote.

The letter, spearheaded by House Minority Whip Steny H. Hoyer (D-Md.), follows a joint resolution issued last week to approve a Metro Safety Commission. The move is intended to encourage Maryland and Virginia to act after those states, and the District, failed to meet a federal deadline to create such an agency.

The legislation grants “the consent and approval of Congress” to the jurisdictions to launch the safety oversight commission, and also details the structure and governance of the agency, reiterating language that appeared in legislation passed two months ago by the D.C. Council.

Rep. Barbara Comstock (R-Va.), the only Republican lawmaker from the immediate Washington area in the GOP-controlled Congress, joined her Democratic colleagues in support of the resolution, but did not endorse the GAO letter.

“We appreciate the request for yet another report, but we have a running list of nearly 40 different reports on Metro from the last ten years,” Comstock spokesman Jeff Marschner said in a statement. He listed reports from a litany of public agencies, departments and think tanks as well as the GAO, “which is the same source the members are sending their request to.”

Comstock, who sits on the House Transportation and Infrastructure Committee, has been working on a bill to overhaul Metro and could use her clout as a member of the majority party to push legislation to the floor. Her staff met with staff from newly sworn-in Transportation Secretary Elaine Chao’s office last week.

Comstock’s bill would establish mandatory criteria for a new compact — which governs how the agency is governed and financed — effectively giving the three jurisdictions an ultimatum to overhaul Metro.

At the same time however, proposed reforms are controversial and could pit the GOP-controlled Virginia General Assembly against the Democratic-dominated Maryland legislature and D.C. Council.

Rep. John Delaney (D-Md.) already introduced a bill that would give the agency an extra $750 million in federal funds over 10 years in exchange for changes in the governance structure and labor contracts.

In addition to Hoyer and Delaney, the following members signed the GAO letter: From Maryland, Sens. Benjamin L. Cardin and Chris Van Hollen and Reps. John Sarbanes, Anthony G. Brown and Jamie Raskin; from Virginia, Sens. Mark R. Warner and Tim Kaine and Reps. Gerald E. Connolly and Don Beyer. Eleanor Holmes Norton, the District’s nonvoting delegate, also signed.