Complex sentence: Five Amtrak E8s were rebuilt with HEP generators for this purpose; in addition, 15 baggage cars were converted to HEP generator cars to allow the hauling of Amfleet by non-HEP motive power (such as GG1s substituting for unreliable Metroliner EMUs).
Split into simpler sentences: Five Amtrak E8s were rebuilt with HEP generators for this purpose. In addition, 15 baggage cars were converted to HEP generator cars to allow the hauling of Amfleet by non-HEP motive power (such as GG1s substituting for unreliable Metroliner EMUs).