The first weekday commute of the third phase of Metro’s year-long SafeTrack rebuilding program resulted in confused riders, crowded platforms, packed trains — and at least one lost shuttle bus Wednesday — but there were no major meltdowns, transit agency officials said.

The third “surge” involves a line segment shutdown between Reagan National Airport and Braddock Road affecting the Blue and Yellow lines, primarily in Northern Virginia. That means no trains are running between those stations.

The work, which will last through Monday, will disrupt the commutes of an estimated 50,000 riders daily, in addition to the thousands of travelers who use National Airport. Then, starting July 12, Surge #4 will shut down service between National Airport and Pentagon City, affecting about 86,000 weekday riders, plus air travelers.

The surges are among 15 that the region will endure between now and mid-March, based on Metro General Manager Paul J. Wiedefeld’s timetable.

Metro deployed shuttle buses to bridge the gap between stations where rail lines are shuttered, and local jurisdictions expanded their bus operations to help meet the needs of riders who abandoned Metro for alternatives. Many commuters used buses, cars and bikes to avoid Metro. Others used car services such as Uber. And some used slug lines. Still, confusion, long waits and crowds were common.

The third surge in Metro’s long-term maintenance overhaul known as SafeTrack runs July 5-July 11 on the Blue Line. Take a look at how it will affect your commute. (Claritza Jimenez,Danielle Kunitz/The Washington Post)

[Here’s how to get to National Airport during Metro’s SafeTrack disruptions]

Metrobus is running shuttle buses between the Braddock Road and Pentagon City stations and, for airport customers, between the Braddock Road and National Airport stations. Metro commuters on one Blue Line train said their shuttle bus driver got confused at National.

Rider Jerry Freese, a grant manager for the U.S. Department of Housing and Urban Development, said he knew something was wrong when the driver stepped off the bus somewhere along Braddock Road and started looking around.

“Then he got back on the bus and started asking people if they knew how to get to the airport,” Freese said. “Obviously, they didn’t train the employees.”

Freese, who was headed to L’Enfant Plaza from Van Dorn Street, said 25 minutes of the trip were spent on the shuttle bus.

“Maybe I’m not going to be back tomorrow,” Freese joked.

Asked about the confusion, Metro spokeswoman Morgan Dye said shuttle bus operations are supported by about 100 operators. About half of the drivers are exclusively dedicated to SafeTrack. But the other 50 operators are not, and some of those drivers might only receive notice that they are working a shuttle route the night before, Dye said.

The third surge in Metro’s long-term maintenance overhaul known as SafeTrack runs July 5-July 11 on the Yellow Line. Take a look at how it will affect your commute. (Claritza Jimenez,Danielle Kunitz/The Washington Post)

“Metrobus training staff are out at various SafeTrack locations to ensure that all operators are familiar with the route,” she said. “Generally, things are going well and any first-day issues will be smoothed out.”

Metro and local officials have encouraged riders to avoid the Blue and Yellow lines during the surge. Those who decided to brave the system Wednesday encountered crowded platforms, trains and buses and in some cases long delays — similar to the previous two surges.

At the Pentagon City Metro station, the platform was so packed with riders waiting for Blue Line trains headed to the District that some commuters even had trouble getting off escalators.

Arthur Hamilton stepped onto the descending escalator and spotted the masses on the platform. He yanked out his earbuds in shock. “Oh my God,” he said, to no one in particular. But it only took a few moments for him to sigh and enter Metro commuter zen mode. “Well — it is what it is,” he said.

[Your guide to riding the Yellow Line during SafeTrack’s third surge]

Mary Wei-Haas, a writer for Smithsonian.com, stood on the platform at the National Airport station and craned her neck, hoping to spy a train. She’d skipped the shuttle bus routine by having her husband drive her to the airport station and was hopeful that a train would arrive quickly. Her prayers were answered — sort of. A train pulled in within minutes — but it was Blue and she’d been hoping for Yellow.

“Well, it is heading downtown,” she said. She pondered her options and then hopped aboard.

A new slug line at the Franconia-Springfield Metro station was empty early Wednesday, but organizers, who started it to help commuters cope with SafeTrack, hope that will change as word of it spreads.

The alternative modes of getting around that were embraced by many commuters weren’t an option for some. Kristina Ament, who is blind, said she and her 9-year-old German shepherd guide dog, Tekla, have their route between their home in Alexandria and her office near Judiciary Square carefully mapped out. They typically walk to the Braddock Road station, hop on Metro and get off at Judiciary Square for her job as an assistant U.S. attorney, she said. They know exactly where to enter and exit each Metro station.

[SafeTrack closures: These D.C. Metro lines and stations will be disrupted in the next year]

At 7:45 a.m., Ament and Tekla stood near the bus bay at the Braddock Road station, waiting for a co-worker who would accompany them on Wednesday’s commute. Ament said they would board the bus to Pentagon City, where they would catch the Yellow Line.

Weary-looking commuters scrambled around them, asking Metro workers which shuttle-bus line they should be in to go to Pentagon City, Crystal City or National Airport. Metro workers in neon-yellow vests shouted out, “Where’re you trying to go?” as ­confused-looking passengers headed toward the line of waiting buses.

With her co-worker’s help, Ament said, the commute via Metro would be “doable.”

“But otherwise this would be a nightmare with all these buses and just trying to figure out which bus line to get in,” she said. “By the time my poor dog figures it out, this surge will be over.”

Ament said she bought a home within walking distance to the Braddock Road station after she found she couldn’t rely on MetroAccess, the region’s paratransit service for the elderly and people with disabilities.

“MetroAccess isn’t reliable enough to get to a job every day,” Ament said. “It’s frustrating.”

The shutdown didn’t appear to affect traffic during the morning commute, with no major delays reported on area roadways.

At 7:45 a.m, traffic was light on Crystal City roads near the airport. Not far to the north, Interstate 395 was crowded, but traffic was flowing across the 14th Street bridge, an area that often becomes a bottleneck.

Arlington County’s transportation director, Dennis M. Leach, said residents have proved nimble during Metro’s first two maintenance projects.

“What we’ve learned from the first two surges is, if you provide the options and really get the word out, our traveling public is resilient. They’ll make adjustments. From an Arlington perspective, so far, so good. It’s worked pretty well,” Leach said.

Yon Lambert, Alexandria’s transportation director, said rail ridership in the affected area was down more than 65 percent Wednesday morning. But buses along routes where Metro was doing repair work were standing-room-only.

“One thing that we clearly have going for us is this is a holiday week,” Lambert said, adding that summertime in general has somewhat lower traffic volumes.

[Looking for an alternative to SafeTrack? Try the ‘original ridesharing’ system: Slugging.]

The Metroway bus rapid transit service stretching from Braddock Road to Pentagon City, in dedicated lanes and with mixed traffic, also helped release some of the pressure, Lambert said. “Having a high-frequency, parallel service during the entire event is a really powerful option for people,” he said.

Lori Aratani, Ashley Halsey III, Mary Hui, Robert Thomson, Martine Powers and Faiz Siddiqui contributed to this report.