The train was pulling into the station about 7:30 a.m. when it experienced a low-speed derailment, a spokesperson for the line said. The third car derailed near lower Monroe Street.
There were 74 passengers on the train, according to the Chicago Fire Department. Four adult passengers suffered minor injuries and were taken to Northwestern Memorial Hospital. The rest of the passengers were safely evacuated.
South Shore trains should be running for the rest of the day while officials assess the situation. One track is still operating.