In 1911, the Central South African Railways placed an experimental Mallet articulated compound steam locomotive with a 2-6-6-2 wheel arrangement in service.

It was also believed that the difference in frequency between the front and rear cylinder exhaust beats would result in a more even pressure in the receiver pipe and therefore improved steam flow, although exactly how this was to come about was not clear.

[2] The unorthodox driving wheel configuration did not have the expected results and in comparison with the other nine superheated engines, the locomotive proved to be inferior in performance.

This device was of the Street type and consisted of a coal crusher, hand-fed by the fireman, which was fitted to the front left hand side of the tender footplate.

The crushed coal then fell by gravity into a chute which led to a receiving bin, fitted below the back buffer beam of the locomotive.

[1][2] The bucket belt was driven by another small steam engine mounted on the left side of the firebox, near the top.

[1][2] It was a very complicated, cumbersome and extremely noisy arrangement which required the fireman to attend to two auxiliary engines and feed the crusher in addition to his normal duties.