The NG G13 was created as the successor to the NG G11 for the two-foot narrow-gauge network. It was significantly enlarged compared to its predecessor and was given an inner carrying axle on each bogie, leading to the 2-6-2+2-6-2T wheel arrangement. While the outer carrying axles were designed as radially adjustable Adams axles, the carrying barrel axles could only be moved laterally according to the Gölsdorf system.

Since the South African government had much better contacts with Germany than with Great Britain at the time, the twelve engines were ordered from Hanomag. At the time of their commissioning, they were the heaviest locomotives in the world built for a gauge of two feet. With the NG G13, the train weights on the narrow-gauge lines could be significantly increased, which even made it unnecessary to convert individual lines to Cape gauge. In Natal, it was used successfully on lines with curve radii of 148 feet and a gradient of 1 in 33.

One of the negative points of the locomotives was that the driver's cab was too small, in which the heat accumulated due to several devices. The crews therefore apparently took advantage of the movable stools and often leaned out of the doors while exploiting the engine's capabilities. The decommissioning took place in quick succession in 1973 after the introduction of the class 91-000 diesel locomotives. Three examples are still operational today, one on the Vale of Rheidol Railway in Wales and one on the Hempstead and Northern Railroad in Texas. All but two of the rest still exist today, but some are in a scrap condition.