Conditions improved and service resumed at the Chicago/State station at 6:55 a.m.
Police said a man was waiting for her outside the restroom, and attacked her as she exited the washroom to return to her booth.
An 85-year-old man trying to catch a Blue Line train was injured and his wallet and credit cards stolen downtown on Thursday.
Police are investigating the death of a man whose body was found on a set of subway tracks along the Blue Line near the LaSalle Street station overnight.
Power was shut off to part of the CTA Blue Line Sunday morning as fire personnel investigate reports of smoke in a subway in the River West neighborhood.