CHICAGO (CBS) — Metra trains on five lines that operate out of Union Station were running up to 45 minutes late Thursday morning, after an Amtrak signal problem briefly halted all trains in and out of the station.

Amtrak spokesman Marc Magliari said “a communication issue between the Amtrak computers and the signals” prevented trains from entering or exiting Union Station starting around 8:45 a.m.

The system came back online and trains were beginning to move again by around 9:20 a.m.

Metra said trains on the Milwaukee North, Milwaukee West, North Central Service, South West Service, and BNSF lines were prevented from going in or out of Union Station due to the Amtrak signal system failure. Those trains were moving again around 9:20 a.m., but with delays of up to 45 minutes.

“Listen to platform announcements for operational changes and delay times,” Metra told riders on its website.