The Arlington County Board voted 3 to 2 late Tuesday to award a $26 million preliminary engineering contract for the Columbia Pike and Crystal City streetcar projects.

Despite the somewhat subdued efforts of streetcar critics and board members John E. Vihstadt (I) and Libby Garvey (D), the board majority backed efforts to move the $333 million project forward. Fourteen residents testified on the issue, with all but two supporting it.

Jay Fisette (D), the County Board chairman, called the decision “a major milestone” toward an anticipated 2020 launch of the line. He and other supporters likened the streetcar construction as just important as the building of Metrorail in the 1970s.

HDR Engineering, which worked on other streetcar projects including the District’s, won the award. Earlier Tuesday, the board voted unanimously to award a $5.6 million contract for street improvements along Columbia Pike. That work is associated with the streetcar project.

Supporters say the streetcar is needed to prompt and accelerate development along Columbia Pike in particular. Two years ago, the board set up a plan that promised no net loss of affordable housing in the region even as new housing, offices and retail was developed.

“The jury is still very much out on whether the streetcar will have a positive or negative impact on affordable housing,” Vihstadt said. “The board majority is playing the old quiz show game of beat the clock. . . . They want to feed the narrative that it’s too late to turn back.”

Also Tuesday, an outside review of what caused cost overruns and delays in building the “$1 million bus stop” along Columbia Pike blamed disagreements about who was in charge, faulty communication and poor execution of construction contracts.

County Manager Barbara Donnellan said the county will oversee the building of bus stops and has procedures to prevent the initial mistakes from recurring.

“As I have said, this project cost too much and took too long,” Donnellan said. “This project was a rare and unfortunate exception to Arlington’s excellent track record of delivering large infrastructure projects in a timely, cost-effective manner.”

The county was supposed to pay the Washington Metropolitan Area Transit Authority $2 million to build three prototype “superstops” along Columbia Pike, at Walter Reed Drive and on both sides of the Pike at Dinwiddie Street.

But when the cost of the Walter Reed station ballooned to $881,933, the county halted work on the other stations and told the WMATA it would not pay more than the $1 million it had already given the transit agency.

Donnellan said the WMATA has taken responsibility for an additional $429,000 in costs incurred before the project was shelved. Canopies that were built for the other two stops will be used as spare parts, repurposed or discarded, she said.

The “superstops” are intended to serve bus and streetcar traffic along the Pike once the streetcar system is built. But the modernist shelter at Walter Reed didn’t live up to its impressive description. The canopy did not keep the rain off passengers and the steel seats were hot in summer and cold in winter, among other issues.

In May, Donnellan announced a redesign that costs 40 percent less and will be used for an additional 23 planned stops, with standardized parts, a lower canopy and no heated flooring. The popular electronic “Next Bus” signs will remain.

The report by the accounting firm CliftonLarsonAllen made public Tuesday cited “a lack of mutual understanding” between Arlington and the WMATA “as to what was to occur and who was responsible at key points.”

In addition, the report said, the WMATA was restructuring its engineering services office and reducing personnel just as the project got underway. Reviews by the Virginia Department of Transportation slowed down the project for four years. Charges and change orders were not put in writing or signed off on by both the WMATA and the county.

Numerous construction errors — such as an incorrect concrete mixture further raised the costs.

The report highlighted confusion about who was responsible for obtaining work permits for the project. The county’s project manager, according to the subcontractor’s notes, agreed to get the permits. But that person — who was not named in the report — left the job in June 2011, and his or her replacement didn’t know about the agreement. Neither the ­WMATA nor the county took responsibility for the permits in subsequent discussions, the report said, resulting in a work stoppage on-site for several months.

“As the report correctly observed, the findings stem from [an] era when Metro was shrinking, rather than expanding, its investment in capital programs,’’ said Philip Stewart, a WMATA spokesman. “Much has changed since that time to ensure clear understandings of roles and responsibilities in shared projects.”

Work on the next eight “superstops” is expected to start in late 2015 or early 2016, Donnellan said.