The HHP-8, is a double-ended electric locomotive manufactured by a consortium of Bombardier and Alstom. HHP-8 stands for High HorsePower 8000. The HHP-8s replaced the GE E60s and supplement the aging AEM-7s on Amtrak's Northeast Corridor, though some of the AEM-7s have been upgraded to AEM-7ACs to match the hauling power of the HHP-8s. The locomotive can haul Amfleet cars at speeds of up to 125 mph. They are sometimes referred to by train crews as "Rhinos".
The locomotives are visually similar to Acela power cars, but they have noticeably shorter and stubbier noses. The HHP-8s are equipped with visible couplers and HEP receptacles at both ends. These are hidden by covers on the front end of Acela power cars during normal operations.
During testing of the equipment between 1999 and 2000 the locomotives experienced a number of problems related to the differing power supply voltages used over the Northeast Corridor. They were designed to automatically switch between voltages, but this feature malfunctioned in testing. Cracking in the trucks was identified as a potential problem during testing. Safety officials at the time felt that potential crack development could be identified before failure with proper inspection.
In August 2002, the HHP-8s were also briefly removed from service when the brackets that connected truck dampers (shocks) to the locomotive car bodies ("yaw dampers") were found to be cracking. The locomotives were then returned to service when a program of frequent inspections was instituted. The damper brackets have since been redesigned and the old brackets replaced with the newer design.