Service to the Chicago Transit Authority's Harlem Station on the Blue Line resumed early Wednesday after the wreckage was removed from a collision two days earlier.
Crews through the night used a crane to lift the damaged train cars from the track and move them out of the way. Power tools were needed in some areas where the cars connected to cut them apart.
A flat-bed truck took the damaged cars to a service yard in Forest Park.
More than 30 people were injured Monday when a four-car out-of-service train, apparently unmanned, crashed into an eight-car train at the Harlem Station just before 8 a.m.
CTA officials still aren't clear what happened or how the out-of-service train got out of the Forest Park yard. Despite multiple systems designed to prevent runaway trains, this rogue train somehow managed to slip out of the yard and travel the wrong way onto the Blue Line tracks.