Three people were in critical condition, Metra spokeswoman Judy Pardonnet said. No one aboard the train was reported injured.
Cars were strewn about the area and other drivers were helping rescue people trapped inside as emergency crews arrived around 5 p.m. Two people had to be extricated from their vehicles, including a woman whose car caught fire after she was out, Marino said.
CBS News reports
The rail crossing where the accident happened cuts through a busy diagonal intersection, and a street sign beside the tracks reads: "Long crossing. Do not stop on the tracks."
CBS station WBBM-TV in Chicago reports from the scene there is a mass of wreckage and metal that is difficult to tell was once cars.
Eye witness Van Jackson told WBBM that due to traffic, cars became sitting ducks on the train tracks. As the train approached, many jumped out of their cars and ran to avoid getting hit.
Elsewhere, other travelers were met with prospect of traffic jams, snowy highways and crowded airports and train stations.
"It's like a hurricane," said Martha Bittencourt, 54, of Sao Paulo, Brazil, describing the Miami airport as she waited for a flight to visit friends in Tennessee.
People who were accustomed to the Miami airport, however, said it wasn't bad. The holiday rush also started out more smoothly than expected at airports in Detroit, Boston, Denver, Minneapolis-St. Paul and the Hartford, Conn., area.
That will change when people head home again, said John Wallace, a spokesman at Hartford's Bradley International Airport.
"What's we're seeing is a staggered effect on the front end," he said. "And then, on the back end, everybody's got to get back for the beginning of the school week and the work week."
CBS News correspondent Sharyn Alfonsi reports that most flights left on time today, but were packed. Aflonsi and crew booked a 10 a.m. flight from New York to Miami to see how bad the travel day was.
The 10 a.m. flight was delayed until noon, and Alfonsi waited at the gate with the Gassner family.
"My husband and I started at 5:30, had the kids up at 6 and left the house at a quarter to 7 to get here for what we thought was a 9:30 flight," said Andrea Gassner, as her 2-year-old son was taking the terminal by storm. "We're trying to keep them both fed, keep the diapers changed. We're hoping we don't run out of diapers before we get to Miami!"