Adobe Stock Photo A 15-year-old boy is facing charges after stabbing a man and assaulting two others Monday and Tuesday on a CTA train. The teenager allegedly approached a 23-year-old man who was sitting on a Purple Line train Monday at the Adams/Wabash station at 201 S. Wabash Ave. and demanded his cellphone, Chicago police said. After the man handed over his cellphone, the teenager demanded the passcode and stabbed the man in the back with a knife, police said. The man was transported in good condition to Northwestern Memorial Hospital, police said The next day, the teen was armed with a knife and robbed a 29-year-old woman who was sitting on a Purple Line train in the 300 block of North Wells Street, police said.