The incident occurred at about 2:35 p.m. before the turnstiles on the Market-Frankford Line concourse at 13th and Market streets, police said. One adult male was taken to Jefferson University Hospital but was later pronounced dead. Police said homicide investigators have been summoned to the scene. A transit police sergeant was on patrol on the eastbound platform at the time of the incident. "While on patrol, he notices across the way, on the westbound concourse, a white male adult, about 30-years-old, and he's being confronted by four, young black males. A disturbance is obvious to him. He goes to investigate,"...