Rush-hour commutes on the Red Line were snarled Friday morning after someone called police about a man with a knife at the Garfield stop on the South Side.
At 5:59 a.m., officers arrived on the platform of the station in the 200 block of West Garfield to look for the armed man, according to Chicago police and the CTA.
95th-bound trains stood at the station for about 30 minutes, while Howard-bound trains were stopped for about 10 minutes, according to CTA alerts.
Officers are currently speaking with one person of interest, police said.
Red Line service in both directions resumed about 6:30 a.m. with residual delays and congestion, the alert said. Commuters were advised to adjust for longer travel times.