Metro Transit has restored service to the Green and Blue light-rail lines after a technical issue paralyzed them for more than three hours Monday.

The agency announced on its X account shortly before 9:30 p.m. that trains were resuming regular service and that passengers may experience only "residual delays."

Around 6 p.m., an error in a system used to control train movements caused all trains to hold in place, spokesman Drew Kerr said. It is not yet clear what caused the error.