One person was killed and at least 100 people were injured, some of them critically.
"I was about 30 feet away from the train when it was pulling into the station. I observed it coming in at a high rate of speed. It went over the bumper block, basically through the air, traveled about another 40 feet and came to a rest when it hit the wall of the waiting room," said Michael Larson, a NJ Transit worker.
Watch Larson's interview here:
Others were nearby and heard the noise first.
"I heard a 'ka-boom!' The whole place shook, just shook, and everybody got quiet, because the first thing you think is a bomb," said William Blaine, who was in the terminal at the time of the crash. "I heard water coming in, so I ran and I saw people all over the ground, debris all over the place."
Blaine described what he saw next.
"New Jersey train employees ran over and they were pulling people out, people were jumping out (with) cuts and bruises. But I didn't realize when I ran, I stepped over a body. There was a dead woman."
Watch our interview with Blaine here:
Ben Fairclough was also in the terminal when the crash happened. He started recording video moments later. Watch his account of the events here:
Corey Futterman was riding in one of the last cars of the train but was not injured in the crash. He told ABC News that this was "something I've never seen before."
"We had just left Secaucus and that's where about half or if not more than half of the train gets off the car to transfer to New York (Penn Station). We were approaching Hoboken and the train did not seem to be slowing down whatsoever and then all of a sudden everything just crashed and shook," Futterman said.
There was no indication that something was wrong before the crash, according to Futterman.
"We were just going a little quicker than expected," he said. "We were not slowing too much."
Massismo Maricaccio said he takes that same train to work every day. He said he noticed that the train wasn't slowing down like it usually does when it enters the Hoboken station.
When asked if the train made any effort to stop, he said "absolutely not."
Watch his interview here:
Another witness, Jamie Weatherhead-Saul of Woodbridge, New Jersey, described the moment of the crash.
"We're panicking, because I believe those people in the front were very badly injured. So they started yelling, because they saw the blood," she said, adding, "(the train) was super packed."
Watch our interview with her here: