Amtrak (former Penn Central, nee Pennsylvania Railroad) interlocking facility. Used to switch trains between 30th St Station's SEPTA's upper level and Amtrak's lower level, as well as the former PRR Main Line to Harrisburg (used by the Amtrak Harrisburg and Pittsburg trains and SEPTA R5 and R6 routes) and the NEC (used by Amtrak's trains to New York and SEPTA's R7 and R8 trains). There once existed a capability to switch trains from the West Philadelphia Freight Elevated, but that has since been removed.