Trains on several Metra lines were delayed Wednesday morning due to "Amtrak emergency station repairs" that shut down three tracks at Union Station, the rail agency said.
Amtrak said the commuter trains were delayed "while Amtrak crews inspected the station area after a report of loose concrete above the track."
An alert from Metra went out after 6:30 a.m. CST, during the morning rush hour, warning riders of delays on the SouthWest Service, Heritage Corridor and BNSF Railway lines.
Union Station South Concourse tracks 2, 4 and 6 were "out of service until further notice," according to Metra, resulting in delays both entering and exiting the station.
Metra also warned commuters that track changes would be necessary, recommending all passengers check gate boards for updated information.
It was not immediately clear how long the delays were expected to last.
Check back for updates on this developing story.