It was intended as a general utility locomotive, capable of operating on 80 pounds per yard (40 kilograms per metre) rail, and was built in two batches by Berliner Maschinenbau and Henschel and Son in Germany.

[1][2][4][5][6][7] At the time, the urgency brought about by the rapidly deteriorating political climate in Europe led to a further 116 locomotives being ordered even before the first batch could be delivered and tested, contrary to usual SAR practice.

The increasing political turmoil in Europe and the resulting urgency, however, prohibited time being spent on designing a new boiler.

To maintain approximately the same tractive effort as the Class 15E, the boiler pressure was raised to 225 pounds per square inch (1,551 kilopascals), at the time the highest yet used on the SAR since the SAR loading gauge did not permit horizontal cylinders of greater bore diameter than 24 inches (610 millimetres) with normal cylinder spacing.

In addition, largely also as a result of the decision to use the shorter Watson Standard boiler, it was decided to reduce the coupled wheel diameter from the originally intended 66 inches (1,676 millimetres) to 63 inches (1,600 millimetres), which shortened the coupled wheelbase and would further ease passage on sharp curves.

Owing to axle load restrictions, however, it was necessary to reduce the water capacity to 9,200 imperial gallons (41,800 litres).

To improve the weight distribution, both tender pivot centres were relocated 6 inches (152 millimetres) towards the rear.

It was proposed to adopt streamlining on some of the Class 23 locomotives which were intended for the Cape mainline and the manufacturers were requested to submit estimates to that effect.

In 1945, the Minister of Transport at the time, the Honourable F. C. Sturrock MP, instructed that a number of Classes 15F and 23 engines should be named after various South African cities and towns and fitted with suitable nameplates in both official languages.

The decorative plates were fitted to the sides of the smokebox or to the elephant ear smoke deflectors of engines which were so equipped.

[10] The new class soon formed the bulk of the motive power on the lines from Touws River to Beaufort West and from De Aar to Welverdiend via Kimberley and Klerksdorp.

[10] Each caboose-working cycle began with the picking up of a string of 34 empty hopper wagons and a guard's van in Bloemfontein.

After electrification of the Postmasburg branch late in 1966, steam only came on at Beaconsfield and crews and engines were once more being changed in the traditional manner at Bloemfontein, Kroonstad and Bethlehem.

They were all retired by 1983, many of them in the process donating their large Type EW tenders to increase the range of the Class 15F.

2556 which was plinthed next to the High School in Gideon Joubert Park in Touws River on occasion of that Railway town's centenary in 1977.