Four were delivered by Société Anonyme John Cockerill of Seraing in Belgium in 1937, twenty-two by Beyer, Peacock & Company between 1939 and 1958, and the last eight by Hunslet-Taylor in Germiston, Transvaal in 1967 and 1968.

[1] When the four narrow gauge branchline systems in Natal were closed down by the SAR, the Weenen and Mid-Illovo lines were torn up.

[6][7] As part of the ACR's strategy to keep the narrow gauge railway competitive, two of its Class NG G16 Garratt locomotives were rebuilt using technology similar to that used by mechanical engineer David Wardale in the creation of the Class 26 Red Devil in 1980, based on developments pioneered by Argentinian engineer L.D.

[1] The GPCS is a single-stage gas producer which achieves an improved combustion and steaming rate, reduces the emission of black smoke and overcomes the problem of clinkering.

[1][9] One visible difference between the original and the rebuilt locomotives is the megaphone-shaped Lempor chimney, which contains a cylindrical mixing chamber and a wide angled diffuser.

The object of the latter is to convert the kinetic energy of the combustion gas and exhaust steam mixture to a pressure as close to atmospheric as possible.

Narrow gauge locomotives like the Class NG G16, on the other hand, have plenty of height available for the exhaust, so a single long chimney was achievable.

141 achieved a fuel saving of 25% compared to a standard Class NG G16 Garratt, a performance which was easily maintained in regular service.

[1] The cost of the work paid off financially within twelve months and led to a proposal to develop a Class NG G17 Garratt.