Signal problems are causing major CTA service disruptions and delays Friday morning in the Loop.

A signal problem near the Clark/Lake station, first reported at 8:46 a.m., disrupted or delayed service on the Brown, Pink, Orange, Green and Purple lines, according to service alerts from the CTA.

Pink Line trains were only running from 54th/Cermak to Polk for nearly two hours, according to the CTA. Normal service in the Loop was resuming as of about 10:30 a.m.

Brown Line service was temporarily halted between Merchandise Mart and the Loop, but resumed with delays as of 9:45 a.m., the CTA said.

Normal service was also resuming with residual delays on the Orange, Green and Purple lines.