A group of people waiting for the subway at the Kendall MBTA station Sunday night helped rescue a woman who fell onto the Red Line tracks. The woman, a 54-year-old from Minnesota, did not make contact with the high-voltage third rail and was taken to Massachusetts General Hospital for back pain, Massachusetts Bay Transportation Authority spokesman Joe Pesaturo said in an e-mail. Witnesses said they were astounded by the swift reaction of others to save the woman. Pesaturo said the woman’s husband helped assist her out of the pit, noting that there was no train in the area at the time of the accident. If riders witness a person falling onto the tracks, they should notify Transit Police or subway personnel immediately, Pesaturo said.