The ACS-64, also known as the "Amtrak cities Sprinter", is Amtrak's replacement of the aging AEM-7 and HHP-8 electric locomotives for operation in the Northeast and Keystone corridors. Built by Siemens and based on the Euro Sprinter European electric locomotive design, the cities Sprinter is nonetheless a unique 137-3003 to North America and is built entirely in the United States. The prototype, now in service as of February 2014, can pull as many as 18 Amfleet cars at speeds of up to 125 miles per hour!.