Between 1974 and 1977, the state-owned South African Iron and Steel Corporation placed forty-four General Electric type U26C diesel-electric locomotives in service.

[1][2][3] The Class 34-500 type GE U26C diesel-electric locomotive, also known as "Class 34-400 ex Iscor", was designed by General Electric and built for the South African Iron and Steel Corporation (Iscor) by the South African General Electric-Dorman Long Locomotive Group (SA GE-DL, later Dorbyl).

To facilitate the larger fuel tank, the inter-bogie linkage found on all other South African U26C models was omitted on these locomotives.

All South African diesel-electric locomotives have their side handrails mounted along the upper edges of their long hoods.

[3] Since c. 2009, other mainline diesel-electric locomotive types also emerged from the Koedoespoort Transwerk shops with running board-mounted handrails after major overhauls.

[5] At some stage during the mid-1980s, all Class 34-000, 34-400 and 34-500 locomotives had saddle filters installed across the long hood, mounted just to the rear of the screens behind the cab on the sides.

[6] Beginning in 2010, some locomotives were equipped with electronic fuel injection and GE "Bright Star" control systems.

On some of the first locomotives to be so modified, externally visible evidence of the modification is a raised middle portion of the long hood.

[7] In 1977, all mainline rail operations on the Sishen-Saldanha iron ore line was taken over from Iscor by the South African Railways (SAR).

[1] Until 2012, when they began to be replaced by new GE Class 43-000 type C30ACi locomotives, most of the Class 34-500s remained on the 861-kilometre long (535-mile) Sishen–Saldanha Orex line to haul ore from the open cast iron mines at Sishen near Kathu in the Northern Cape to the harbour at Saldanha in the Western Cape.

During the 1980s several were observed working goods and passenger trains between Port Elizabeth and Bloemfontein and between Beaufort West and Kimberley, still clad in their Iscor livery.

In the 1990s some of the Class 34-500 units began to be repainted in the Spoornet orange livery with a yellow and blue chevron pattern on the buffer beams.