A 16-year-old boy is accused in at least four robberies at CTA train platforms since July, police said. The boy, who isn't being identified, was charged with armed robbery, three counts of aggravated battery to a transit employee or passenger and three counts of robbery, police said. He was arrested Monday at the Juvenile Detention Center, 1100 S. Hamilton Ave., after being identified as one of the offenders who participated in multiple robberies and batteries of men on train platforms earlier this year, police said.July 31 in the first block of West Cermak Road on the Near South SideSept. 17 in the 3900 block of North Sheridan Road in WrigleyvilleSept. 17 in the 1100 block of West Brywn Mawr Avenue in EdgewaterSept. 18 in the 1200 block of North Clark Street on the Near North Side