Update, 8/6/19, by Gaspard Le Dem: 

Metro’s Silver Line extension has a tangible opening date, at least according to one transit agency.

The Metropolitan Washington Airports Authority tells DCist that the Silver Line to Dulles Airport and Loudoun County will open on or around July 16, 2020, which had been revised earlier this summer after several construction delays.

“Give or take a few days, that’s the date we have come up with based on the analysis of materials given to us by our contractors and by statistical analysis,” says Marcia McAllister, a spokesperson for MWAA.

WTOP first reported the potential start date.

The transit authority has figured out ways to work around significant delays reported by contractors last June, according to McAllister.

“It looks like a lot of that work can be done simultaneously rather than stretching it out,” she says. “Instead of doing that work one at the time, they can have crews working on all of their problems.”

MWAA is overseeing construction on the project, but the ultimate decision about the first day of service rests with the Metro Board. And WMATA isn’t committing to a start date yet.

“Metro will establish a revenue start date once the project (including the rail yard) has been completed to our standards and requirements, and accepted by Metro for final testing and safety certification,” spokesperson Ian Jannetta told DCist in an emailed statement.

Original: The extension of the Silver Line has hit new delays, according to the latest progress report from the Metropolitan Washington Airports Authority, the agency in charge of the project.

Capital Rail Constructors, which is working on stations and tracks, is approximately eight months behind schedule, and Hensel Phelps, the contractor responsible for constructing a rail yard for the project, is more than a year-and-a-half behind. The latest progress report says that between March and April, Hensel Phelps “slipped” an additional 67 days behind.

Will Thompson, the vice president and district manager for Hensel Phelps, said the delays have to do with changes in “testing criteria” for the rail yard. Per the report, the rail yard’s critical progress needs include testing, safety and security certification, and HVAC installation.

The contractors are projecting that the rail yard, tracks, and stations are all scheduled to be completed by the end of July 2020—but the Metropolitan Washington Airports Authority has not approved the schedules.

The first phase of the project opened in 2014 with five new stations (McLean, Tysons Corner, Greensboro, Spring Hill and Wiehle-Reston East), the first new Metro line since 1991. The second phase will add another six stations, including a stop at Dulles International Airport. The Silver Line extension was originally slated to open in 2018 before a slew of changes pushed the timeline back (the delay added at least $95 million to the project’s price tag).

Cracks in concrete structures were found as far back as 2015. In April, the Washington Post reported a raft of problems with the project—including cracks in concrete pedestals at the Dulles Airport station, and an impasse over how to deal with hundreds of flawed concrete rail ties. (The rail ties provide support in areas where multiple tracks come together.)

In April, according to the progress report, “discussions continued among the Airports Authority, WMATA, and CRC and its vendors and subcontractors to mitigate the delays.”

The report also said that Hensel Phelps and the authority were “actively and collectively making efforts” to speed up the completion of the rail yard.

Keith Couch, project director for Capital Rail Constructors, said repair work on the pedestals will begin within the next two weeks, and the group is in discussions with both Metro and the airports authority over its revised special track design to address the concrete rail tie issue.

Starting in October, Capital Rail Constructors will have to pay the authority penalties if it fails to deliver the project by its scheduled date for substantial completion: August 7. Marcia McAllister, a spokesperson for the airports authority, told WAMU via email that Hensel Phelps’ scheduled date for substantial completion was December 18 of last year.

“That was not achieved,” wrote McAllister. “We are currently in negotiations with them for the costs of the delays.”

Thompson of Hensel Phelps said the parties were still working on determining “a mutually agreeable schedule” for completion of the project.

This project, the second phase of work on the Silver Line, is the first time a Metro extension is being done by private contractors and not the transit agency itself. The contractors will hand the project over to Metro once their work is substantially complete. At that time, Metro will take approximately two months to test the tracks before passengers can begin traveling on the new portion of the system.

ATU Local 689, the union representing most of the area’s transit employees, has expressed concern about what it has called “privatization” of the Metro system. Metro has accepted proposals from a number of companies interested in managing the new portion of the Silver Line — a move Metro’s General Manager Paul Wiedefeld has said would “hold down pension cost growth.” A Metro spokesperson said the proposals, which were due last month, are currently under review.

Barry Hobson, the chief of staff for Local 689, recently told WAMU that Silver Line privatization, and an ongoing dispute over transit worker pensions, are likely to be points of contention in the union’s next round of contract negotiations with Metro. The contract negotiations will begin at the start of next year.

This story originally appeared on WAMU.