Commuters wait for trains at the King Street station in Alexandria that was closed this summer. (Astrid Riecken for The Washington Post)

Four-year-old Arshiya Naoaj was up early Monday, her dad said, excited to get back to the morning routine she’d missed all summer: riding Metro.

“She woke up early to celebrate,” Shah Naoaj, 32, said, laughing as Arshiya ducked behind his back at the Van Dorn station about 8 a.m. “It’s really exciting. We’re glad those dark days are gone.”

The “dark days” to which he refers are those of the summer-long shutdown of six Blue and Yellow line stations south of Reagan Nation Airport. The stations, closed since late May for a massive platform reconstruction project, reopened Monday, on time.

Arshiya and her father were among roughly 17,000 commuters whose regular routes — through either the Braddock Road, King Street-Old Town, Eisenhower Avenue, Huntington, Van Dorn or Franconia-Springfield stations — were disrupted or derailed for much of the summer.

For the Naoajes, that meant their morning commute from Alexandria to downtown Washington — he to his job as an economist, she to child care — ballooned from a 40-minute ride to a two-hour slog that required multiple bus switches and, on especially dark days, an expensive Uber.

As he paced around the Braddock Road station early Monday, greeting riders and surveying the scene, Metro General Manager Paul J. Wiedefeld acknowledged the frustration but said the work was necessary to keep the system safe.

“It’s been a long summer for our customers . . . no doubt about it,” Wiedefeld said. “We had to do it. It was a safety issue: If we didn’t do it this way, we would wake up one day and have to shut it down.”

The King Street station is one of six stops that reopened Monday. (Astrid Riecken for The Washington Post)

The $200 million project, Wiedefeld said, represents a new era of accountability in which, “when we get a safety issue, we get on top of it.”

This shutdown was the first step in Metro’s plan to rebuild 20 station platforms by the end of 2021.

Metro board Chairman Paul C. Smedberg marveled at the new LED lights illuminating the station. Other smaller-scale fixes included nicer platform and bus shelters, larger screens to display train schedules, an improved audio system for station announcements and USB ports in every shelter.

“I think the first thing I noticed was the lighting, the feel of it,” Smedberg said. “I think the stations look great.”

Smedberg was one of several top officials Metro deployed to greet returning riders Monday. Metro Treasurer Craig Gross spent the morning roaming the Braddock Road platform, a shiny blue “Hello Again” badge affixed to his suit, as he answered commuters’ questions and distributed complementary Metro tote bags.

Mary Chris Chapman, 65, who has commuted to work via Metro for about 13 years, said the station “smells like a new car” and looks like one, too — “clean and beautiful.”

Rider Chris McLennon, 49, called the station’s “changed ambiance . . . futuristic.”

Others focused on the floor. Light rain began to fall about 9 a.m., prompting travelers at the Braddock Road and Van Dorn stations to test out the new, slip-resistant platform tiles. Larger and more porous than their predecessors — though colored the same shade of rust red — the tiles are supposed to provide better drainage, minimizing the chance of puddles.

Metro General Manager Paul J. Wiedefeld takes a train from Braddock Road station to King Street station. (Astrid Riecken for The Washington Post)

“It’s so great they replaced these because everyone slipped on them,” said Celeste Carter, 66, an employee of the National Science Foundation who has ridden Metro to work for more than a decade.

Mostly, though, riders rejoiced in the sudden truncation of their commutes. As they stuffed their belongings into Metro tote bags or munched on free doughnut holes provided by a former Alexandria City Council member, commuter after commuter detailed shutdown horror stories.

Alexandria resident Brianna Watkins, 28, said the closures added an extra two hours to her travels. Watkins, who works in security in downtown Washington, had just given birth to her second child when the shutdown began.

“Just getting back to work after having him was a lot, and then this,” Watkins said as she waited on the Van Dorn platform with Kimora, 5, and Shiloh, 5 months. “It was at exactly the wrong time for me.”

Some riders documented their excitement on social media. One man filmed the arrival of an approaching train via Snapchat for his friends, real-time proof that the stations were up and running. Another woman traversed the Braddock Road station end-to-end to curate a celebratory collage of photos — including at least one selfie with a platform sign — before sending it to her fiance.

Commuters board trains at Braddock Road station. (Astrid Riecken for The Washington Post)

Alexandria resident Howard Scott, on the other hand, was a little disappointed in having to give up the “pretty nice setup” he had during the shutdown. The 56-year-old federal employee was allowed to work from home for the duration of the closures.

Though he missed his colleagues, he’d grown used to the casual, comfortable environment.

“I was able to dress kind of scruffy,” Scott said as he stood on the Braddock Road platform, eyeing his dress shoes and slacks.

Wiedefeld said riders’ reaction to the reopening was almost uniformly positive. He is not anticipating a post-shutdown dip in ridership; “people will come back because we’re reliable,” he said.

So far, the few complaints he has received are nearly all about the same thing. The contractor used the wrong font in signage at at least two of the rebuilt stations: Helvetica Black, instead of Helvetica Bold.

Metro plans to fix the typeface, Wiedefeld said, though he is unsure when that will happen.

“I saw a conspiracy theory that this was the first step in changing all the fonts,” Wiedefeld said, laughing. “C’mon people, we’re not that sophisticated!”