A problem with a smoking piece of equipment along a track of Metro’s Green Line led to a chaotic and dangerous scene Wednesday evening as dozens of riders took it upon themselves to evacuate a train and then tried to find transportation as they filled the streets around the Anacostia and Navy Yard stops.

The incident, which lasted more than two hours, started shortly after 5 p.m. as Green Line trains began single-tracking between the Navy Yard and Southern Avenue stations because of a third-rail issue near the Anacostia stop. The situation involved an “arcing insulator,” a part on the track that keeps electricity from the third rail away from other parts.

If a bolt on the insulator is loose or the part has other problems, transit experts said, it can create smoke. D.C. fire officials who responded to the scene found burning insulation fueling a small fire that produced smoke in the tunnel, said Lon Walls, a D.C. fire department spokesman.

But in trying to safely take down the power to the affected outbound track, one of the emergency responders hit a switch in a box that shut down power along a large segment of the track. That left two trains that were waiting to go through the single-tracking area without power, meaning about 2,000 passengers were stranded, a Metro spokesman said.

Passengers on one of those trains evacuated by themselves and began trying to walk toward the Anacostia station. But another train was on the tracks in front of them.

Metro spokesman Dan Stessel said that between 50 and 150 passengers on the six-car train went onto the track bed — a dangerous move given that power was live on the other track.

Emergency personnel helped the passengers evacuate through a vent shaft that took them into Anacostia Park. Metro Transit Police officers went onto the train to “reassure customers that the [safest] place to stay was on the train,” Stessel said.

One woman reportedly had a seizure aboard a train at the Navy Yard station. D.C. fire officials said three people were taken to hospitals; one was listed in serious condition, and two had minor ailments. None were considered life-threatening.

Stessel said Metro sent “dozens of buses.” But it could not accommodate the hundreds of passengers a train can hold, so some riders were forced to find other ways to get home.

Riders said there was little information from Metro about which buses to take or when they would arrive. Those on the underground trains said the trains were crowded, hot and dark.

“No safety procedures were given,” said Farrah Garcia, who had been heading to the Southern Avenue stop. “People start panicking when they don’t hear anything for two to three hours. Metro can do better.”

Rail service was restored about 7:15 p.m., Metro said.

By 8 p.m., the crowds started to diminish as rain began to pour down. The incident was the second in a week in which riders have been stranded on a train. On Sunday, riders were stranded for two hours on an Orange Line train after the train lost power. Last summer, riders also left a Green Line train on their own.

Queen Collins, who was on one of the trains that got stuck Wednesday, said she helped a woman who had an asthma attack on her train. Collins also said a pregnant woman was on the train. Despite that, no medical aid was offered to riders, she said.

“They didn’t offer us anything, any water to drink,” Collins said.

Passenger Shanca Santiago, 20, said she was heading from Chinatown to pick up her 6-month-old son in Congress Heights. “They said 10 minutes . . . and that was two hours ago,” she said. “This is so unorganized.”

Santiago said that when she got off the train at Anacostia, she found no information on how to get to Congress Heights.

“And they keep trying to raise fares,” she said. “I’ve been waiting on a train for two hours, and they say I can’t use the bathroom. Are you serious? I’m still holding my bladder.”