The Cummins QSX 15 is a 15 liter I-6 engine rated 500 kWm at 1900 RPM. Emissions control is accomplished with optimized fuel injection, optimized combustion, and the application of the Cummins Diesel Particulate Filter (DPF). The DPF is a passive system and accomplishes NOx of 1.5 gms/HP-HR, PM of 0.03 gms/HP-HR, HC of 1.4 gms/HP-HR, and CO of 2.6 gms/HP-HR (EPA Off-Road Diesel Certification). R. J. Corman Railpower expects that Locomotive Level Testing will demonstrate full compliance with the Locomotive Tier IV Emissions regulations that come into effect in 2015.