One person was killed and 83 injured when a five-car Chicago Metra commuter train went off the rails this morning on the city's south side. The train, inbound from Joliet, was carrying 189, including four crew members. Seventeen of the injured were in serious or critical condition.

Chicago city officials asked for assistance from suburban emergency response teams. Emergency vehicles and a helicopter were quickly at the scene of the derailment, which happened a few minutes after 8:30 a.m. Saturday. The injured were taken to six area hospitals.

Chicago firefighters work on a derailed Metra commuter train, Saturday, Sept. 17, in Chicago. (AP Photo/Brian Kersey)

Stephanie Smith, who was sitting in the upper tier of the second car, said she heard brakes screeching, then the train came to a halt. "I just went flying into the safety seat bar and fell to the ground."

Smith, a master's student at DePaul University, told the Chicago Tribune, "We were skidding out of control. Weaving back and forth. People were weeping and screaming."

Television pictures showed the train's engine tilted at an angle, with the car behind it off the tracks. The second and remaining coaches were well back from and disconnected from the engine and first car.

The second car was damaged on one side and had broken windows. There were broken rails and smashed ties for several metres.

Chicago firefighters work the scene of a Metra commuter train derailment, Saturday, Sept. 17, in Chicago. (AP Photo/Brian Kersey)

Metra spokeswoman Judy Pardonnet said all track signals were working when the derailment occurred but she did not have any other details on a possible cause.

The speed limit there is 25km/h. Pardonnet said she did not know how fast the train was going.

The engineer had been operating Metra trains for six months, following six months of training that included trial runs on the same Joliet-to-Chicago route and more than five years as a CSX Corp. freight train engineer. The "badly shaken" engineer was taken to a hospital for routine drug tests.

The U.S. National Transportation Safety Board and other agencies are investigating.