The first three locomotives were all working in Natal soon after entering service.
All but one remained there for the rest of their service lives until withdrawal by 1962.
No.
NG51 was later returned to the Avontuur line to replace the retiring Class NG3 no.
NG5 as yard shunter at Humewood Road.

After completion of the Otavi Railway's gauge widening by April 1961, a flood of Class NG15 locomotives from South West Africa swamped the Humewood Road depot in Port Elizabeth.
From a total of 23 engines in March 1961, of which four were sub-shedded at Loerie, the number almost doubled to 43 by July.
As a result, no NG51 was officially retired by July 1962.

The two locomotives of the second order also served in Natal, ending up working on the branch from Estcourt to Weenen.
In 1964 they were both transferred to the Avontuur line in exchange for two newer Class NG G13 locomotives.
In Port Elizabeth, they were employed on shed and yard duty and on transfer trips to and from the docks until, after the arrival of the Class 91-000 diesel-electric locomotives in 1973, they were withdrawn from service in October 1974.
The first three locomotives were all working in Natal soon after entering service. All but one remained there for the rest of their service lives until withdrawal by 1962. No. NG51 was later returned to the Avontuur line to replace the retiring Class NG3 no. NG5 as yard shunter at Humewood Road.
After completion of the Otavi Railway's gauge widening by April 1961, a flood of Class NG15 locomotives from South West Africa swamped the Humewood Road depot in Port Elizabeth. From a total of 23 engines in March 1961, of which four were sub-shedded at Loerie, the number almost doubled to 43 by July. As a result, no NG51 was officially retired by July 1962.
The two locomotives of the second order also served in Natal, ending up working on the branch from Estcourt to Weenen. In 1964 they were both transferred to the Avontuur line in exchange for two newer Class NG G13 locomotives. In Port Elizabeth, they were employed on shed and yard duty and on transfer trips to and from the docks until, after the arrival of the Class 91-000 diesel-electric locomotives in 1973, they were withdrawn from service in October 1974.
South African Class NG G11 2-6-0+0-6-2