The woman was walking on the Green Line platform at Cermak about 7 p.m. when a male suspect shoved her, police said.
She fell onto the "track area," and the suspect fled the scene, according to CPD.
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The woman was helped back onto the platform and then taken to a local hospital to be treated for head and arm injuries, CPD said.
Chicago police are investigating the incident; no additional information about the suspect was immediately available.