About 200 people were finally evacuated from the stalled-out frigid ice box that lost heat and power near the Greens Farm station in Westport around 8:45 p.m.
A downed wire was blamed for the incident, with a rescue train finally arriving a little over two hours later to take them to their destination.
They arrived in New Haven just before 11:30 p.m.
Passengers on the train tweeted that it felt like they pulled down a power line, and one reported seeing a big flash and a lot of rumbling.
One passenger said the rescue train was delayed in getting to them because of a stuck switch.
The incident was not expected to greatly impact the Thursday morning commute, though New Haven line customers were told to anticipate delays of up to 20 minutes due to weather-related conditions and wire damage in the vicinity of Greens Farms.