The G12 and G8 are low-cost general service locomotives produced by General Motors from 1955 to 1970. The basic points of the original project defined the production of a versatile, simple, economical locomotive, adaptable to various gauges and with diverse applications, both for service in branches and in main lines.
They were built in the BB or A1A-A1A versions, with or without dynamic brakes, and sold to a large number of countries such as Brazil, Cuba, Mexico, Venezuela, Colombia, Chile, Argentina, New Zealand, Australia, South Africa, Nigeria, Iran, Indonesia, Egypt, etc. They were, until recently, the most popular locomotives in Brazil, still in use in all regions of the country. The biggest difference between the G-12 and the G-8 eg number of cylinders and the power of the diesel engine, V-12 with 1425 HP and V-8 with 950 Ho, respectively.