Metro riders who got stuck on a Green Line train last week are disputing Metro's account of the stoppage, which resulted in many riders walking along the tracks to get home.

The case shows a confusing scenario for all involved, further highlighted on Friday evening when a derailment on the same line, just a few stops away, ended with an orderly evacuation led by firefighters through an emergency exit shaft. That's how things are supposed to go in the system, which has 122 emergency exits and safety protocols.

But on Tuesday, a Green Line train stopped running between Prince George's Plaza and College Park about 5:50 p.m. Riders said the train had no power, meaning no air conditioning on a day when temperatures hit 98 degrees. The transit agency told the Washington Post that it had to cut power to its tracks when riders started walking on the tracks toward College Park, causing more delays including to the rescue train en route. An agency spokesman had said what the riders did was not safe and that Metro strongly discourages riders from leaving on their own in "self-evacuations."

But riders said they didn't flee until learning that the rescue train had also lost power -- and once the train operator told them they could leave.

"The conductor eventually told us that we could leave 'if we wanted to' because the third rail had no power, not the opposite way around," Metro rider Natalie Bailey told The Washington Examiner.

Making matters worse, she said, they had to pay when they got to the station -- at the new, higher rates enacted Sunday.

Twitter messages from Bailey and some other riders reflect their account.

At least four others also contradicted Metro's account of events in comments posted on the Post story.

"Nobody left the train until we heard the announcement that the train coming to push us into College Park had also lost power! That was when people started to get off," wrote someone using the name mojo_rising_71 who claimed to be in the front car.

But Metro spokesman Philip Stewart said that some riders initiated an evacuation. Then, he said, the train operator and Metro Transit Police did a "directed evacuation" for those who remained on board.

"Once customers were on the roadway, continuing the evacuation was the fastest way to resolve the situation," he said.

However, he said he did not have additional information about when and why the rescue train stopped. He said officials were still trying to reconstruct what happened. They plan to discuss it at a safety meeting with board members on Thursday, he said.

It also is not yet clear, he said, what caused the initial train or the rescue train to stop. Officials were also still investigating Friday's derailment.

Tuesday was not the first time that riders have fled onto the tracks. Last June, riders left a Red Line train near Rockville after a woman made comments about a bomb that riders construed as threats. The woman was taken in for a mental evaluation and no bomb was found.

But the agency said that self-evacuation caused more problems as they had to shut down power to a large section of track on the Red Line, causing major delays during the morning rush.