CHICAGO, May 28 (UPI) -- The commuter derailment Wednesday in Chicago was caused by a 31-year veteran of the Chicago Transit Authority, an official said.
CTA President Ron Huberman said the train derailment happened when an unidentified train operator ran through a red signal indicating the track switch at the junction ahead was not properly set for the train, the Chicago Tribune reported.
When the train operator proceeded, an emergency device stopped the train automatically, Huberman said.
The southbound elevated transit train derailed about 10 a.m. At least 31 people were injured when four cars of the commuter train left the track.
At least 29 people were taken to hospitals and others were treated at the scene on Chicago's South Side near 59th Street and Prairie Avenue, WLS-TV in Chicago, reported.
Officials said commuters traveling south of Garfield/55th are encouraged to take Red Line service and transfer to a 63rd bus at the Red Line 63rd Street station.
Green Line service on the Harlem/Lake branch is not affected by the accident, they added.
