Police are warning residents a few collection of armed robberies this month close to the 79th Street Red Line station in Chatham on the South Side. In every case, a number of males have approached riders, hit them and robbed them at gunpoint, in response to a neighborhood alert from Chicago police. The first theft occurred about 11 p.m. within the 7900 block of South State Street, police mentioned. Two others occurred at 9:10 p.m. Jan. eight and 1:30 a.m. Jan. 10 on the platform on the station, 15 W. 79th. The suspects had been described as a number of males between 22 and 29 years outdated, police mentioned. They stood 5-foot-5 to 5-foot-9, weighed 140