Nearly every CTA line was operating with residual delays Monday morning, causing headaches for commuters bearing the single-digit temperatures to get to work.

Red Line trains bound for 95th Street were operating with residual delays due to police activity at the Wilson station, 4620 N. Broadway, and the North/Clybourn station, 1599 N. Clybourn Ave., according to the CTA.

Officers responded at 8:26 a.m. to a call of a battery at the station, but couldn’t find a victim, according to Chicago Police.

Police did not immediately provide information about the incident at North/Clybourn.

Blue Line trains bound for Forest Park were facing residual delays due to both a mechanical problem at the Montrose station, 4600 W. Montrose Ave., and a sick customer at the Chicago station, 800 N. Milwaukee Ave., the CTA said.

Service was being restored on both lines, the CTA said.