A small crowd watches as a new streetcar is rolled onto the rails along H Street Northeast, near the intersection with 4th St. in Washington, in this December 2013 file photo. (Eva Russo/For The Washington Post)

Back in January, Mayor Vincent C. Gray donned a fluorescent yellow vest and hopped on one of the District’s new red-and-gray streetcars. Gray (D) had said passengers would be riding the line by February. But it wasn’t ready, and the mayor, then in the midst of a reelection campaign, had to settle for a consolation prize: a test run along H Street NE and Benning Road with a handful of workers and cameras on hand.

Gray is not the only one who has been disappointed.

Shortly after Gray’s less-than-triumphant photo op, D.C. Council member Mary M. Cheh (D-Ward 3) grilled top transportation officials about when residents, commuters and tourists would be able to hop aboard. Three months later, there’s still no clear answer.

“This is really frustrating,” Cheh, chair of the council’s transportation committee, told officials at a recent hearing. “We tell people it’s going to start this year, then it’s next year. Then this season, then it’s next season. I guess I just believe it when I see it.”

More than a half-century after Washington’s last streetcar stopped rolling, the city is struggling to get its new system running. After years of false starts, delays in the construction of a maintenance facility have helped complicate a far-reaching series of tests and safety certifications. Transportation officials won’t publicly offer a target date for opening day, saying it will come as soon as the system’s ready and receives necessary safety approvals.

Despite the halting progress, the District’s ambitious streetcar project still has a big thing going for it: a major financial commitment from city leaders. Last year, Gray and the council — including Democratic mayoral nominee Muriel Bowser (Ward 4) and presumptive independent candidate David A. Catania (At Large), who are running in November to replace him — set up a large, recurring source of revenue for the project.

Gray’s proposed capital budget for the streetcar — covering engineering and construction and the streetcars themselves — totals $810 million over the next six years. That would go toward building a 22-mile streetcar system crisscrossing the city. Gray also is proposing to more than double the operating budget for streetcars to $10 million in 2015, which would cover the bulk of what it costs to run the system.

Transportation officials, citing what they called conservative projections, said they expect to take in about $500,000 in fare revenue during the first year the H Street/Benning Road line has paying passengers. That’s based on the assumption of a $1 fare, though they noted that they are recommending a higher fare of perhaps $1.50 to $2 per trip.

Repeated efforts by transportation officials to boost fares on Circulator buses from $1 to $1.50 with SmarTrip cards, or to $2 cash, have been rejected by council members, and the final decisions on streetcar fares remain in flux.

Transit advocates say subsidizing users is part of operating major public transportation systems, and that the benefits of streetcars are worth the costs. Connecting richer and poorer swaths of the District will bring the city closer together, officials say, and streetcars will play an important role in transporting the growing population in a place with little room for new roads. They also expect increases in property values and investments near the lines, as has already happened along H Street, and are projecting a boost in city tax revenue.

Skeptics see the mirror image of that cost-benefit analysis, saying ridership in the system won’t justify the hefty investment. They warn that the streetcars, which will share the traffic lanes on H Street and Benning, could further clog an already crowded corridor, and that buses would be a more nimble and efficient option, one without overhead wires, which some criticize as unsightly. And they say District developers have already proved they don’t need a projected streetcar line as a draw to invest.

Three District mayors — Anthony A. Williams (D), Adrian M. Fenty (D) and Gray — have backed the streetcar vision, joining cities such as Portland, Ore., Seattle and Cincinnati. Last year, the D.C. Council voted to dedicate a steady stream of funds to the project for years to come. They changed city law to set aside 25 percent of projected local revenue increases, based on calculations using next year’s numbers, for the project.

Those funds, which the city expects to total more than $200 million annually within a few years, “shall be budgeted for the Streetcar Project until the construction of the streetcar system is complete,” the law says.

The District also is seeking federal money to help underwrite future lines. Officials said this month that they are seeking $20 million to fund part of a $64 million project to extend a partial line in Anacostia that is being used as a test track. Linking communities near the Anacostia Metro station and Joint Base Anacostia-Bolling would spur development “through neighborhoods that have experienced under-investment for several decades,” Del. Eleanor Holmes Norton (D) said in a letter to U.S. Transportation Secretary Anthony Foxx.

The District plans to extend the 2.2 mile H Street/Benning Road line from behind Union Station to K Street and west to Georgetown. On the line’s east end, plans call for continuing on to the Minnesota Avenue and Benning Road Metro stations.

Since the first streetcar was slowly slid onto the H Street tracks in December, project leaders have been making their way through a complex series of construction and safety tests that officials said will continue for months. Some tests remain on hold while construction of a key maintenance building continues. District safety officials need to certify the completed system before it can open to the public, and their federal counterparts also are reviewing project safety.

Gray’s hopes for a February launch were overly optimistic.

“Obviously, we want things to move as fast as possible. But sometimes you get to the point where things are really out of your control,” said Gray spokesman Pedro Ribeiro. Delays in the delivery of new streetcars helped slow things down, he said, and transportation officials “underestimated the regulatory process” for getting the system certified.

“It’s frustrating to have these things happen. But at the end of the day we know that once the system comes on line it’s going to be just a massive improvement for District residents,” Ribeiro said. “It’s an investment in the future that we believe the vast majority of D.C. residents support.”