The G8 and its variants are diesel locomotives built for export by EMD and its Canadian subsidiary which have low axle loads. 382 of the original G8 were built for service in ten countries. They had a V8 variant of the 567-series engine with 875 hp and were built for four different track gauges from metre to 1,600 mm (5 ft 3 in). While the basic variant had four axles, a variant for even lower axle loads had two A1A bogies. The latter became the BB200 in Indonesia and class DB in New Zealand. The Victorian Railways class T built by Clyde Engineering was similar, but the later ones already had the new 645-series engine.

The GL8 was a variant that was much shorter than the original one and also somewhat lighter. Here again the standard version had two two-axle bogies. 96 were built, of which 69 went to Brazil, 15 to Ireland and twelve to Tunisia. An A1A-A1A version was built with 41 for Bangladesh and twelve for Taiwan. Additionally, Queensland Railways ordered twelve of a six-axle version that was designated class 1700.

The GA8 was an extra light variant that weighed only 52 tons and had 800 hp. The bogies were of the standard freight car type and the traction motors were suspended below the frame, transmitting their power via cardan shafts to the axles. The wheel base of the bogies was only 5 ft 8 in or 1,727 mm to enable them to run through tight curves. Most of the 94 GA8 went to Argentina, El Salvador, Mexico and Taiwan.