Red Line trains were temporarily rerouted to elevated lines Thursday morning after a report of smoke in the subway.
The smoke was reported near the Jackson station about 9:35 a.m., according to CTA spokeswoman Catherine Hosinski. No injuries were reported.
The trains were rerouted to the elevated lines between the Fullerton and Cermak-Chinatown stations.
The cause of the smoke was not immediately known, Hosinski said, but as of 10:30 a.m., normal operations were resuming.