A 30-year-old subway rider was stabbed in the chest and left arm as he sat on a train in Brooklyn late Tuesday, authorities say. The man was on a northbound Q train near Seventh Avenue and Park Place in Prospect Heights when he was attacked just after 11 p.m. He was taken to a hospital and is expected to survive. Authorities had no description of the suspect, nor did they have information on the circumstances of that led to the stabbing. It also wasn’t clear if the victim was sleeping at the time. Anyone with information is asked to call Crime Stopper at 1-800-577-TIPS.