"It was more people because a lot of times people kind of sit by themselves. I actually had someone sitting with me this time, so I couldn't stretch out like I like," said Katrina Atkins, a South Shore commuter.
Trains operated on their regular schedule Wednesday morning, but there were a reduced number of trains in service because 18 cars are still trapped at Millennium.
"In this time you got to jump on that first train because you never know if you are going to make it down here to get out," said Josephine Osborne, another commuter.
The derailment suspended westbound service Tuesday afternoon. Maintenance crews worked through the night to clear the scene and bring service back to normal.
Investigators were still looking into what caused the train to go off the tracks.
Cell phone video shows one of the middle train cars touching a pillar, indicating the train may have hit it. Officials described the incident as a "low speed derailment."
Two people sustained minor injuries.