The Class NG 6 4-4-0 locomotives were bought second hand by the SAR in 1915 to supplement the remaining locomotives on the various narrow gauge lines in South Africa after any spare engines had been sent to South West Africa.  Thirteen engines were bought, but only nine were put in service, presumably the other four were used for spare parts.  They were numbered 96 to 98 and 101 to 106.  Only No. 104 is known to have worked on the Ixopo Branch, probably only for a short time until the Class NG 3ís returned from South West Africa.