The G26 is a diesel–electric locomotive built in the US by General Motors Electro-Motive Diesel for export and in Australia by Clyde Engineering under licence.

The G26 was developed to increase traction capacities on the tracks which supported lesser axle loadings.

The Victorian Railways purchased 18 G26C locomotives built in Australia by Clyde Engineering, called the X class.

Queensland Rail purchased 102 GL26C-2 locomotives in 1970, locally built by Comeng as sub-contractor for Clyde Engineering, and known as the 2100 class.

The JŽ 664 locomotives were originally acquired by the Yugoslav Railways; after the breakup of Yugoslavia the class were split between Serbia, Croatia, and Slovenia.

Upon privatization in 1997, the 30 units still in operation were transferred to ALL- América Latina Logística (Latin America Logistic).

[citation needed] The Indonesian State Railways purchased 15 G26MC-2U locomotives in 1986, classified as CC202 and numbered from 01 - 15.

Beginning in 2010 a new numbering system was introduced, inserting two final digits of the date of manufacture of the locomotive.