Authorities are searching for three people suspected in robberies of passengers on a CTA Red Line train on the North Side.The robberies began about 10:50 p.m. Tuesday on a southbound Red Line train in the 1100 block of West Bryn Mawr Avenue in Edgewater, Chicago police said.The next robberies happened shortly afterward in the 3900 block of North Sheridan Road in Lakeview and in the 1200 block of North Clark Street in Old Town, police said.In each case, the three robbers approached riders and battered them, then took their personal belongings before forcing the passengers off the train, police said. Related CTA’s high violent crime rate keeps away what’s needed to ward off crime — passengers CTA Blue Line killings a mirror held to society The robbers — two males and a female — are described by police as Black, between 14 and 20 years old and of differing heights and weights.One male wore a black and gray hooded sweatshirt, the other male wore a black and red long-sleeve shirt, and the female wore a gray hooded sweatshirt during the robberies, according to images released by police.Anyone with information is asked to contact Chicago police at (312) 745-4447 or submit an anonymous tip to cpdtip.com.