Police said the 28-year-old man was standing on the Addison station platform at 3622 West Addison when he jumped onto the tracks in front of the train.
The Chicago Fire Department responded to a call for a person pinned underneath a train around noon.
Police said he was pronounced dead at the scene.
The Cook County medical examiner's office confirmed the fatality.
As of 3:27 p.m., service on the Blue Line resumed with delays. Trains were not stopping at Addison.
The investigation is ongoing.
Some Blue Line trains are operating w/residual delays after an earlier medical emergency on the tracks at Addison. Service resuming.— cta (@cta) March 8, 2017
Blue Line trains are not stopping at Addison due to prior medical emergency on the tracks. Shuttle bus avail btwn Belmont to Irving Park.— cta (@cta) March 8, 2017
EARLIER CTA TWEETS
Blue Line service continues to be disrupted between Jeff Pk–California from med emergncy, shuttle bus & train avail: https://t.co/uzp9WhIEns— cta (@cta) March 8, 2017
Blue Line service has been temporarily suspended between Jefferson Park and California due to a medical emergency on the tracks— cta (@cta) March 8, 2017
Blue Line service has been temporarily suspended between Montrose and Logan Square due to a medical emergency on the tracks.— cta (@cta) March 8, 2017
Blue Line trains are standing at Addison due to a medical emergency on the tracks; crews working to restore service.— cta (@cta) March 8, 2017
The Chicago Sun-Times Media Wire contributed to this report.