This is cowardly behavior. Chicago police are looking to identify men suspected of striking CTA patrons through the windows of trains at Red Line stops. Two incidents were reported last week in which the offenders opened the side operator window on the CTA train, and hit people who were standing on the platform as the train departed.
CTA patrons hit by men through windows of departing trains. See story here. https://wgntv.com/2019/02/27/cta-patrons-hit-by-men-through-windows-of-departing-trains-police-say/