Cars, trucks pedestrians and streetcars share the road along H Street as tests continue on the streetcar line Dec. 22, 2014 in Washington. (Katherine Frey/The Washington Post)

Broken pieces of rail have already appeared. Streetcar doors scrape against platforms. Switches that guide 35-ton vehicles from one stretch of track to another occasionally don’t work.

In a new assessment released Friday, outside experts found “no fatal flaws” in the District’s fledgling streetcar system. But there are flaws, and many are serious.

That didn’t stop Mayor Muriel E. Bowser’s administration from deciding to stick with a project that has stymied her predecessors with questions of mismanagement and cost. Now, Bowser’s team has promised to open the streetcar to the public, cheering longtime backers even as the time frame remains uncertain.

“We have the independent third-party assessment that we needed. But there’s a lot of work ahead,” said Leif Dormsjo, head of the District’s Department of Transportation.

Dormsjo, a former top Maryland transportation official appointed by Bowser (D) in January, brought in an inspection team from the American Public Transportation Association to help him decide a fundamental question: Can the system — $200 million in the making and years late — ever safely carry passengers?

Their answer: Yes, as long as the city provides “appropriate resources and commitment” — and works through a list of 18 fixes.

And so, Dormsjo, who has said the streetcar project’s conception and execution had a lack of discipline and “orderly thinking,” has pivoted from existential questions to intensely practical ones. His assignment from Bowser is to get a plan, get it right and get the 2.2-mile line on H Street and Benning Road NE open.

Bowser becomes the fourth successive District mayor who has tried to get streetcars running again. The last time they carried passengers through town, John F. Kennedy was president.

Among the report’s recommendations: bringing on “a technically capable Project Manager,” repairing onboard radios, installing proper markers so operators know where to stop at each station and passengers can safely get on and off, and making sure all six streetcars are running.

Beyond the list of 18 “identified tasks,” questions remain on future streetcar strategy and spending, and on past mismanagement.

To meet his immediate pledge of “stronger management discipline,” Dormsjo said he’s ticking through key tasks. In one crucial though belated step, he plans to hire a project manager and other specialists with specific streetcar expertise to better oversee the project and the large team of outside consultants who have driven much of the effort.

“The current team has worked hard under tough circumstances,” Dormsjo said. “But we recognize we need greater in-house experience with streetcar and transit operations and maintenance. Part of our work plan includes strengthening the public sector management team in those areas.”

The causes of some of the problems remain unclear, he said. The cost of fixing them all is also unknown. Take the handful of broken rails, most of which are in the maintenance yard, Dormsjo said. Dealing with “rail breaks,” as they’re dubbed in the industry, is part of running a railroad, he said. Amtrak gets them; so does Metro. But they are a “safety-critical” matter, and officials need procedures in place for quickly fixing them before they get worse and “you have a derailment.”

The affected stretches of rail need to be removed. “We need to pull the breaks out to diagnose exactly what the cause is,” Dormsjo said. “But it can be related to how the steel was manufactured. It can be related to the weather — they cropped up during the cold season. It can be related to how the brakes on the vehicles are calibrated. And it can also be related to how the tracks were installed and how it was actually embedded.”

Then there’s the problem the outside experts called the “streetcar/station platform interface,” also known as streetcar doors scraping on platforms.

Fixing that is key to safe boarding. The doors must open smoothly. The gap between the vehicle and the platform can’t be too wide. Pedestrian walkways must not be gouged. And the doors must not rust, Dormsjo said. The problem is “very correctable,” he said, either by raising the streetcar or shaving the platforms.

“We need to get some specialists in there to help engineer the right solution,” he said.

Problems with switches — which shift cars onto other tracks near Union Station, at the Benning Road maintenance yard, and at a major intersection in between — are “episodic,” Dormsjo said. “Some of them are not springing back automatically.”

Dormsjo saw switch problems with the MARC Train when he worked in Maryland.

“It’s just a matter of figuring out what’s going on,” Dormsjo said. “Was there a construction issue we need to retrofit and fix? Is there maintenance that needs to occur? Are we operating the vehicles in a certain way that’s creating a kind of sticky switch?” The switches are also a correctable problem, “but one you really have to nail down before you get to passenger service.”

One of the first tasks is one of the most basic — coming up with a master list and schedule for everything that needs to be done before the first passengers board.

The Federal Transit Administration had asked the District for just such a master schedule of safety, construction and testing tasks early last year. But the administration of former mayor Vincent C. Gray (D) — which was intent on opening the line by the end of Gray’s term, specifically by November 2014 — still hadn’t produced one as of early December, according to federal transit officials. The transportation association that produced the assessment last week emphasized the importance of such a centralized tracking document.

“They looked at the records,” Dormsjo said. “There really had not been that type of rigorous scheduling activity under the prior administration.”

Dormsjo said streetcar officials and consultants will have workshops on the identified problems to come up with a detailed plan.

“We’re going to have people who are going to really challenge our assumptions and our team’s work plan and make sure we’re accounting for risk properly,” Dormsjo said. Once it’s finally set, “I’m going to have to hold the team accountable to that schedule,” he said.