More than 40 people were on the train. But no one was seriously injured.
The four employees were suspended shortly after the derailment. They have filed a grievance. Their union is filing a class action lawsuit on their behalf.
"The Local 308 does not believe that the four employees who were involved are the sole responsibility for what happened," said Robert Kelly, Local 308 president.
Kelly says that all four are excellent employees and adds the CTA is liable for the derailment.