Service on the Chicago Transit Authority's Brown Line resumed at about 8 p.m. Friday, just about four hours after an unmarked police car collided with a passing train.
Though the impact severely damaged the squad and slighly pushed at least one train car off the track, one police officer and the train's engineer were only slightly injured.
Deputy Chief John Escalante said two officers, one on foot and another in the squad car, were following someone. The female officer in the squad tried to make it across the tracks and was struck by the westbound train.
CTA spokeswoman Lambrini Lukidis said the car went around the downed gate.
About 30 to 40 passengers were removed from the Brown Line train and transported using shuttle buses. The CTA shut off power in both directions between the Kimball and Western stations.
"No one on the train was apparently injured, but the train engineer did complain of probably just some anxiety-related issues," said Escalante. "When you walk up and look at it, it does look like it could be worse, but fortunately the officer does not appear to have very serious, life-threatening injuries."
Mike Lazar, owner of the Chaldean Hair Salon across from the site, said he heard people yelling and screaming in the street after the crash.
He has seen at least a dozen such crashes in his 15 years of doing business at the site.