Metra said an inbound train from Waukegan to Ogilvie Transportation Center struck a woman who was walking along the elevated tracks just north of the Central Station.
Trains were moving again both directions shortly before 5 p.m. Extensive delays through the afternoon and evening commute are expected, Metra said.
No further details about the incident or the woman have been released. Riders should visit metra.com for updates on the service disruption.