According to this post on progressiverailroading.com:
PowerRail Inc. recently announced the formation of PowerRail Engine Systems, a full-service engine company. PowerRail Engine offers rebuilt engines, as well as new and remanufactured power assemblies, governors, turbochargers, water, fuel, and oil pumps, and other engine related components. Parts and components support both EMD and GE engines, including Tier 0+ emission kits. In addition, Environmental Protection Agency emission-compliant equivalents are available on most major components, according to a company press release.