Trains on the Metra BNSF line were halted in both directions near suburban Cicero early Thursday, with massive delays expected to last into the morning rush hour.
Inbound and outbound trains were stopped around 5 a.m., Metra tweeted, due to downed electrical wires and poles.
A spokesman for Metra said a freight train hit low-hanging power lines, which remained on the train as crews responded to the scene.
The incident took place near the Cicero station, located at West 26th Street and South Cicero Avenue, officials said.
The extent of the delays, and how long trains would be halted, was not immediately clear.
Metra officials recommended commuters use the Union Pacific West line as an alternate route.
Check back for updates on this developing story.