Old Pueblo Trolley is a non-profit, educational corporation based in Tucson, in the U.S. state of Arizona, that is dedicated to the preservation of Arizona's mass transit history. The name also commonly refers to the heritage streetcar line which OPT began operating in 1993, on which service is currently indefinitely suspended. OPT consists of three divisions that each fill a specific role in preserving the state's mass transit history. The divisions are the Street Railway Division, Motor Bus Division and the Museum Division (Southern Arizona Transportation Museum).