An alternative locomotive diesel fuel study included testing a wide variety of fuels in full-sized engines. The fuels tested included methanol and ethanol, shale oil product. SCR II, carbon black-diesel oil slurry, sunflower oil, residual-diesel fuel oil blends, and off-specification middle petroleum distillates. The laboratory test facility includes EMD and GE full-sized engines and smaller research engines. Testing includes engine performance, long-term idle, and 500-hour wear tests. Some promising fuels are field tested in locomotives operating in normal service.