It’s official: Metro’s summerlong line-segment shutdown will end on time, meaning the six Blue and Yellow line stations that have been closed since late May will reopen as scheduled Sept. 9, the agency said.

Transit officials said Monday that workers are on track to complete the mammoth platform reconstruction project on the stations south of Reagan National Airport as planned. Officials were concerned an extension might be necessary.

“The word is, we’re not going to extend the opening date,” Metro board member Christian Dorsey said Monday morning during a panel discussion featuring Northern Virginia elected officials. Dorsey echoed the message Metro General Manager Paul J. Wiedefeld delivered in a radio appearance Friday.

“We’re very close, and it’s going very well. So I expect us to hit the 9th,” Wiedefeld said on “The Kojo Nnamdi Show.” Only Mother Nature, in the form of a major disruptive storm, could get in the way of the Sept. 9 reopening, Wiedefeld said.

That’s good news for the 17,000 riders who use that portion of the system daily and have endured the disruption at Braddock Road, King Street-Old Town, Eisenhower Avenue, Huntington, Van Dorn and Franconia-Springfield stations, which have been closed since May 25.

The 107-day shutdown is the first phase of a three-year project to rebuild 20 of 45 outdoor platforms that Metro says are “structurally deficient” and pose safety risks to riders. The reconstruction work is necessary, the agency said, to avoid an emergency shutdown. Work next summer will affect eight stations on the Green and Orange lines — Vienna, Dunn Loring, West Falls Church, East Falls Church, West Hyattsville, Prince George’s Plaza, College Park and Greenbelt. Metro is expected to have more details about that work this fall.

In this first phase, Metro is spending about $200 million to rebuild and modernize platforms. The most important fix was to level the station platforms so they line up with the floor of train cars, eliminating a wheelchair impediment and a trip-and-fall hazard for exiting passengers. This was a major problem at Braddock Road, where the platform had been noticeably lopsided since the station opened in December 1983. The infamous “Braddock hump” will be gone when the station reopens in 14 days.

The shutdown also allowed workers to complete other large-scale projects, including repair of a rail bridge near the Van Dorn station, the installation of a new crossover near King Street, and the repair of another crossover at Huntington, according to Metro.

Besides addressing significant safety concerns, transit officials say the upgrades will enhance the rider experience. As part of the improvements, Metro has installed slip-resistant tiles, stainless-steel platform shelters with USB charging ports, and energy-efficient LED lighting throughout the stations. Announcements should be clearer via an improved speaker system.

And the stations will be equipped with larger screens where those waiting for a train can track arrival times as well as other service alerts.

Metro spokeswoman Sherri Ly said in the next two weeks Metro will be testing the station equipment, including the new intercoms, platform information displays, fire and life safety systems, power, and lighting.

“Track personnel will inspect the rail infrastructure with a track geometry vehicle, and as we get closer to reopening test trains will begin running through the area,” Ly said.

Earlier this month, there were questions about whether the Van Dorn Street station would fully reopen Sept. 9, or whether single-tracking would be necessary while one side stayed closed for repairs until early October. Ly said Monday that Metro is “making every effort to provide normal service on the Yellow and Blue lines when the stations reopen September 9.”

At the Monday roundtable organized by the Arlington Chamber of Commerce and other Northern Virginia chambers, Alexandria Mayor Justin Wilson (D) welcomed the news of the on-time opening, citing the impact the shutdown has had on Alexandria commuters.

“It’s definitely been a difficult summer for us in Alexandria, and certainly that extended to the county as well, taking away, essentially, the linchpin of our transportation infrastructure, as well as our economy,” Wilson said. “This affected not only our residents, but it also affected our businesses, who were inhibited both from their customers getting to them as well as their employees. We heard plenty of stories from businesses where their employees left and went to other employers because they just couldn’t get to work.”

Wilson said many residents learned to use buses and the water taxi. Although Metro has provided a shuttle service to ferry passengers from the six closed stations to other parts of the rail system, many commuters have turned to other options, including local bus services, carpooling and biking.

Madeleine Mitchell, a Blue Line commuter who lives in Old Town and travels from King Street to McPherson Square in downtown Washington daily, said a little extra planning and time helped her this summer. She was dreading the shutdown in May, and with two weeks left to the disruption, she says she’s just looking forward to it being over.

“[I] cannot wait to see all of the nice improvements,” said Mitchell, a rug designer who runs a gallery downtown. She walks to the King Street station where she catches the Metro shuttle to National Airport to connect with the Blue Line, which she rides to McPherson.

Metro officials want riders like Mitchell to know the Metro option will soon be back.

Wiedefeld, in his radio appearance Friday, acknowledged that it’s possible that some riders might not come back to Metro after trying other travel alternatives this summer. But he said he is confident riders will like the changes.

“I think (it) will be a lot different from what they experienced when they were there before,” Wiedefeld said. “But more importantly, at the end of the day I think we offer a very reliable service that is a great alternative to a lot of other alternatives they have, particularly traveling by car.”