The NG G16 was a direct development of the NG G13. The biggest differences were that the carrying axles now ran in roller bearings and the inner carrying axles were no longer just laterally adjustable, but radially adjustable. The first four locos came from Cockerill in Belgium and only series 2 to 4 came from Beyer, Peacock. The seven series 4 engines had larger supplies as they were originally intended for the Tsumeb Copper Corporation and then delivered to the SAR. The last eight locomotives came from Hunslet-Taylor in South Africa in 1967 and 1968 because Beyer, Peacock had stopped building steam locomotives. They were the last new steam locomotives that the SAR received. From 1989, two locomotives were modernized with knowledge that was also used on the “Red Devil”. 