NEW YORK (CBSNewYork) – Sunday is one of the busiest travel days of the year. It’s when most people head home after Thanksgiving.

For passengers on one Amtrak train headed to Boston, the commute became a living nightmare.

The Amtrak Acela train was stuck for at least six hours outside of Penn Station, apparently due to a power problem. By the time the train pulled into Boston Sunday night, nearly 12 hours had past.

“We left at 9:40 on time. We pulled out of the tunnel. About five minutes out of the tunnel, we stopped,” passenger Nicholas Yeh told CBS2’s Marc Liverman. “They didn’t tell us much until they started to tell us… the connections to the wires were broken. It was maybe an hour, an hour and a half when they finally started opening the doors to the cabins so that we could start getting more fresh air. One of the bad things though is that without power, none of the bathrooms flush.”

Yeh praised the conductors, saying they have been communicative with the passengers. They told passengers that due to where the train had become stuck it wouldn’t be safe for them to get off.

“The power went off very early and we didn’t really know what was happening when it just stopped. After about 30 minutes they made an announcement, saying there was trouble,” said passenger Sabrina Fleischman. “Because the toilets are powered by the power, we had no power, so they couldn’t flush. So they were all backed up, and they ended up closing all the bathrooms, because it was unsanitary for people to actually go in there.”

Amtrak connected a diesel engine to help move the train, Yeh said.

The long delay on the train rattled passengers.

“Nearing four hours, people started to get a little bit unsettled,” said Fleischman. “They were complaining to, I believe it was the conductor and the people working, telling them there was an odor coming out of the bathroom.”

At one point, one passenger wound up calling the police because Amtrak wouldn’t let the passengers leave, Fleischman said.

Experts believe the number of people flying could set a record, with the TSA potentially screening more than three million travelers.

“Normally for us we’re in the low two millions. So to get up to three million, that’s a significant surge,” said TSA Administrator David Pekoske.

If you’re driving and hoping to avoid post-Thanksgiving traffic, experts say you should have left Saturday.

They urged drivers traveling Sunday to leave before 3 p.m., after which traffic is expected to be the worst in New York City.