On the Eastern System, problems were experienced with the low-grade local coal from the Cyphergat and Molteno collieries in the Stormberg.

[1][3] John D. Tilney, the Eastern System Locomotive Superintendent, carried out many experiments in an attempt to overcome the coal problem.

Some of these involved modifying some of the 4th Class locomotives in order to install oscillating firebars and larger fireboxes.

[1] Another modification by Tilney was an extended smokebox, to make room for a very efficient spark arrester which was constructed of wire mesh.

In 1881, the General Manager appointed Hawthorne R. Thornton as Chief Locomotive Superintendent for the whole of the Cape of Good Hope, in response to the "growing tendency on the part of the several Locomotive Superintendents to bring in modifications of designs in essential parts of the engines and rolling stock".

[1] At the time these 4th Class locomotives entered service, the two Eastern System mainlines were open to King William's Town and approaching Sterkstroom respectively.

[1][2] At some stage after 1904, three of these locomotives, numbers 470, 471 and 477, were sold to the Kowie Railway Company, which operated a line between Port Alfred and Grahamstown.

They were considered obsolete by the South African Railways, designated Class 04 and renumbered by having the numeral "0" prefixed to their existing numbers.