Power was shut off to the rails while CTA crews evacuated 14 passengers to the station about two blocks away.
One lane of the Dan Ryan Expressway was closed as crews worked to get the train back on the tracks. It took crews a couple hours to restore service.
One man was treated for an asthma attack.
An investigation is now underway into what caused this derailment.
"We are investigating the cause right now. We are looking at all the options and we are going to interview the operator as part of our normal standard procedures," said Noelle Gaffney, CTA.
"I think we was stopping at the signal line but then he passed it and then he had to back up but when he backed up it derailed," said Justin Murray, CTA train rider
Last Wednesday, a Green Line train derailed near 59th and Prairie. Fourteen people were injured. The CTA blamed operator error for that derailment.
