Beginning on January 1, 1972, export customers now had the option to purchase EMD Dash 2 electronics on new orders of locomotives.

Customers who did purchase EMD Dash 2 electronics had the -2 suffix applied to the end of the locomotive's model designation.

To provide high horsepower in the passenger service, EMD installed Vapor Clarkson boilers for Head End Power on the GT26 series.

One of the earliest South African Narrow Gauge export customers for the GT26 Series, the South African Railways purchased custom built GT26MC locomotives that were equipped with lightweight frames shorter than standard a GT26 frame by 1 ft (304.8 mm) as well as a six axle (C) interlinked trucks.

The locomotives received the M suffix which identifies the lightweight frame as well as Universal type traction motors for 3 ft 6 in (1,067 mm) rail operation; thus Metric would be the understood term.

Only the Estrada de Ferro Vitória a Minas was the sole purchaser of the GT26CU-MP locomotive model for use on its Narrow Gauge (U) rail lines.

These locomotives are easily identified due to their full-length fuel tank, disappearance of the battery box cabinet, and a rectangular windshield on the engineer's side of the cab.

Only Zambia Railways purchased the GT36 series with six axle (C) universal traction motors (U) and microprocessor (-MP) controlled computer electronics – designating the model as GT36CU-MP.