In 1927, the South African Railways placed ten Class HF Modified Fairlie articulated steam locomotives with a 2-8-2+2-8-2T "Double Mikado" type wheel arrangement in service.

[1][2][3] The Class HF Modified Fairlie locomotive was designed and built by Henschel and Son to the specifications of Colonel F.R.

It was the Modified Fairlie equivalent of the Class GE 2-8-2+2-8-2 Garratt which was similar in both size and mechanical respects.

The two engine units were virtually identical and could be interchanged by a slight alteration in the arrangement of their steam pipes.

The locomotives were fitted with Lambert sanding gear with eight sanders, four in front of four wheels in either direction of running.

[2] The locomotive had Pyle National electric headlamps which were fitted to brackets above the end buffer beam of each engine unit rather than at the top of the bunkers, to allow the lights to follow the curvature of the track.

[2] As built, the locomotives were not successful, with the result that they were staged for some time while the Mechanical Engineer of the Durban workshops, G. Ramsay, carried out experiments with the blast pipe arrangement.

[2][5] The pivot bearings were also subject to quite rapid wear since they carried a considerable additional vertical load concentrated on the centre of the engine units as a result of their water and coal bunkers which were mounted on the main frame instead of on the engine units like those on the Garratt equivalent.

The Central South African Railways (CSAR) introduced Gould knuckle couplers on the rolling stock of its Limited Express and Imperial Mail passenger trains in 1904.