Hundreds of customers were reportedly sent out in the summer heat after two trains were disabled on the Red Line this morning.
More remained trapped underground while emergency units responded at the scene, according to reports.
MBTA spokeswoman Lydia Rivera said two, six-car trains, were stuck in the outbound tunnel near the Porter Square station.
A southbound train went disabled between Porter and Harvard, said Rivera.
When a second train came up from behind and tacked on to pull the disabled train back to Porter, it also broke down.
Bus replacement service was started between Harvard and Alewife, she said.
The Cambridge Fire Department responded to the scene and medical attention was provided to anyone who felt like they were suffering from heat stroke or exhaustion.
Tweeters were ruffled by the delays, reporting they sat inside the disabled cars for close to two hours, until they were finally evacuated and taken down the tunnels and out of the station.
Customers also started questioning how the MBTA could consider expanding services in other areas when current lines don’t run properly.
But one customer trapped for more than three hours said she didn’t mind.
“It was actually a lot of fun,” said Michelle Johnson, 22.
Johnson said while it was frustrating to be trapped for so long, passengers on her train made the best of it by making acquaintances, taking photos and engaging in general conversation.
Johnson also applauded the MBTA staff for their friendly service and for keeping passengers updated during the ordeal.
“I mean honestly, I had fun. The people that I was stuck with were great and we had a good attitude,” she said. “We talked and took pictures, one person was making a documentary with their cell phone."
"We joked about the situation," she said.
Johnson said the cabs were air conditioned for about the first hour underground, but shortly after they went off.
She said the situation got sweaty, but wasn’t overwhelming.
“It is sort of expected living around here. It’s life, these things happen,” said Johnson.
- PHOTOS: What's Brewing in Steamy Hallows, the Harry Potter-Inspired Cafe19 Pictures
- PHOTOS: Frida Kahlo at the Brooklyn Museum doesn't hold back23 Pictures