The Philadelphia trolleybus system forms part of the public transportation network serving Philadelphia, in the state of Pennsylvania, United States. It opened on October 14, 1923, and is now the second-longest-lived trolleybus system in the world. One of only five such systems currently operating in the U.S., it presently comprises three lines, and is operated by the Southeastern Pennsylvania Transportation Authority (SEPTA), with a fleet of 38 trolleybuses, or trackless trolleys as SEPTA calls them. The three surviving routes serve North and Northeast Philadelphia and connect with SEPTA's Market–Frankford rapid transit line.