The EMD GT22CUM1 is a narrow gaugediesel-electriclocomotive built by EMD. It has six axles in two trucks, giving it a C-C wheel arrangement. The name means a C-C locomotive, U for metre gauge (the rails are a metre apart), 12-cylinder 645 series. They were built for service in South America by the Villares with license of EMD. The Rede Ferroviaria Federal Sociedade Anonima (RFFSA) a state railroad in Brazil bought about 55 in the early 1980s in order to expand their locomotive roster. The RFFSA needed a powerful single-engined locomotive with light weight per axle for their metric system, and the GT22 represented the highest-rated model that EMD had to offer at the time.
However, a big locomotive such as an SD40 with its three-axle trucks wasn't readily adaptable to the RFFSA's narrow gauge trackage. The smaller traction motors of the meter gauge locomotive were able to handle the full current capacity from the 2.450 hp prime mover. And so, EMD proposed the metre gauge version of the Flexicoil-C three-axle trucks, similar to those found under the export EMD GT26CUM locomotive model, creating the GT22CUM in the process.
