A critical juncture of the Red Line was taken out of service for more than two hours Monday morning after a stray electrical current caused smoke to appear in the tunnel outside Gallery Place, resulting in significant delays for thousands of commuters.

The problem became apparent just after 10 a.m., when a Metro staff member reported smoke on the Glenmont-bound side of the tracks. The tracks between Union Station and Metro Center were taken out of service, and the electrified third rail was shut off so firefighters and Metro staff could investigate the problem.

It took a while — and in the process, officials narrowed the service shutdown to the stretch of tracks between Union Station and Gallery Place — but they finally found the culprit: a stud bolt, one of the metal components that helps to hold the rails in place. The bolt had overheated because of stray electricity running from the third rail into the ground.

Stray current can often be attributed to standing water on the tracks, debris inside a tunnel, or dirt or oil that has accumulated on the insulators that support the third rail, though Metro spokesman Dan Stessel said it was unclear what caused the stud bolt to become electrified in this case.

“Electricity, like water, will always find a path of least resistance,” Stessel said.

Some riders were concerned that the delays would potentially waylay the baseball fans headed to Navy Yard station on the Green Line for the Nationals season opener. Metro directed passengers to avoid the Red Line where possible and use other transfer points to switch to the Green Line.

Riders complained that Metro was slow to provide information about what was happening. And it was the latest disruption to frustrate customers fed up with the near-daily service problems coupled with the inconveniences caused by the agency’s year-long SafeTrack maintenance program.

An arcing insulator disrupted Red Line service in February, and there was a major service meltdown during a morning commute in January, shortly after Metro announced that this year’s focus would be getting the system “Back2Good” in an effort to win back riders who have fled the system in droves.

Riders, however, complain that they’ve seen little improvement from all the work and inconveniences. Service and communication remain sluggish, they say.

“Would be nice if #wmata made announcements at the impacted stations that #redline suspended. No one at Farragut N had a clue,” one rider tweeted Monday.

The Red Line problem was coupled with another disruption for game-goers. The ascending escalators at the west entrance for the Navy Yard station shut off just after noon, after a safety sensor was activated. It took 15 to 20 minutes for the escalators to be reset, although the escalators on the east side of the entrance continued to function.

“I made it!! Helluva trip in on that Red Line death trap. Thank goodness for Uber,” tweeted Dustin Williams, 46, who was headed to the Nats game.

Crews repaired the damage and service resumed shortly after noon, although delays persisted.

Electrical arcing is an issue that continues to be a challenge for Metro, even as General Manager Paul J. Wiedefeld argues that the state of the tracks is improving.

In a report to the House Oversight Committee last week, Wiede­feld pointed out that over the course of 2016, the agency reduced track-related delays by 7 percent over the previous year.

“As we work to improve Metro, I have sought to make it clear to our customers, employees, and the entire region that ‘Safety Trumps Service,’ ” Wiedefeld said in the report. “While speed restrictions and other safety actions may be inconvenient, these actions are evidence that safety is now our number one priority.”

Stray electric current is also one focus of a new nighttime preventive maintenance program that Wiedefeld plans to launch after the conclusion of SafeTrack in June. The preventive maintenance program — the reason Wiedefeld fought to cut back late-night service — will allow Metro repair crews to check track components for early signs of overheating and repair small problems before they become full-on smoke incidents or track fires.

But those long-term plans are little comfort to riders such as Victoria Oms, 26, who took to Twitter to vent about the unplanned disruption Monday.

“So the Red line is on fire. Again,” tweeted Oms, who was traveling downtown from Fort Totten. “I’m going to miss an appointment due to Metro being on fire. Again.”

Oms opted for the Yellow/Green line, then transferred to Blue/Orange/Silver to disembark at Farragut West station — a roundabout route that added 20 minutes to her expected travel time. She was indeed late for her doctor’s appointment.

But the bright side? She didn’t miss it.

Dana Hedgpeth contributed to this report.