Panic over a false rumor of a fire inside a stalled SEPTA train in Center City on Wednesday evening caused passengers to flee the train onto the tracks, resulting in a massive snarl for commuter rail traffic that lasted throughout the night.

The panic began after 5 p.m., when a Paoli-Thorndale Line train leaving Suburban Station for 30th Street Station suddenly came to a halt between stops, said passenger Jeanine Heck, 40, of Narberth.

"There was no electricity, the lights went off, and it was really hot," Heck said.

Scott Sauer, assistant general manager for operations at SEPTA, said an electrical breaker tripped twice on the No. 2555 train, which was carrying 500 passengers.

"When an electrical breaker trips on a train, it makes a very loud bang," Sauer said. "The fact that it tripped twice, for two bangs — that likely triggered the passengers to believe something was wrong."

Heck said that after the train stopped, people sat in their seats at first. But after about 15 minutes had passed, some passengers began talking about a fire and soon most rushed for the emergency windows.

Once riders made their way onto the tracks, all train service was stopped in Center City as a precaution.

Brandan Mackowsky, 23, of Ardmore, also was on the train when panic erupted.

He said conductors told passengers there were overhead wire issues that caused the train to stop. Then there was a sound that some people thought was from the wires sparking, and the conductors told everyone to move to the back of the train.

Some passengers weren't moving, causing others to get angry.

Then, Mackowsky said, "someone started screaming, 'There's a fire on the train!' "

That's when people rushed off the train, at first through the windows and later through the doors, which were opened to try to get people back inside.

"I stayed on the train because there was no fire and no reason to panic," Mackowsky said, adding that he believed people started saying there was a fire simply to move people along faster.

"Of course, it's the hottest day in September when this happens," he added.

The passengers were transferred to another train, but an issue arose and they were transferred again to another train.

Finally, about 6:25, Heck and the original passengers were on a train moving toward 30th Street.

No injuries were reported.

The episode, however, led to misery for riders throughout the system. SEPTA reported lengthy delays into the night, even after train service through Center City resumed.

Earlier, in Suburban Station, Jane Cary, 58, said she had thought taking Regional Rail into the city would be cheaper and more convenient than driving. She had come into Philadelphia from Chestnut Hill West station for a women's business seminar and had expected to depart on a 5:15 train.

An hour later, she was still sitting on a station bench,  waiting, a list of delayed trains at her back.

"Standing. Sitting. Waiting," she said, describing her time at the station. "Right now my feet hurt."

Arthur Shaw, 43, called his kids to let them know he would be late for dinner after seeing the delays at Suburban Station. He was supposed to leave for Lansdale at 5:47, but saw his train would be late so he didn't arrive at the station until 6.

A half-hour later, he was still waiting. He uses Regional Rail daily to get to work at a media company and is used to delays of seven or eight minutes, he said. Wednesday's wait was extraordinary, but he, like many of those waiting at the station, was sanguine about the inconvenience.

"It comes with the territory," he said. "Some days it's going to happen and some days it doesn't."

SEPTA will conduct a full investigation into what happened, Sauer said.

Staff writer Jason Laughlin contributed to this article.