Between 1952 and 1954, the South African Railways placed forty Class 4E electric locomotives with a 1Co+Co1 wheel arrangement in temporary service on the Natal mainline and from 1954 on the mainline from Cape Town across the Hex River rail pass to Touws River in the Karoo.

[4] The Class 4E had a 1Co+Co1 wheel arrangement, with an additional bissel truck at the outer end of each of the two three-axle powered bogies.

[1][4] Since the completion of Eskom's high-tension power feeds in the Cape was late, the first locomotives to be delivered in 1952 were placed in service on the Natal mainline while awaiting electrification from Wellington via Worcester to Touws River.

The problem was hunting which became increasingly severe at higher speed and the units were therefore employed mainly on goods traffic until 1956, by which time their bogie faults had been ironed out.

E247 and one other for between four and six weeks, working from the Electric Running Shed at Braamfontein, before the locomotives were forwarded to Cape Town.

The tunnel system would have enabled a single Class 4E locomotive to haul 1,000 ton trains up the resulting 1 in 66 (1+1⁄2%) gradients.

[1] The Hex River tunnels scheme (Hexton) was initially started in 1945, but was deferred indefinitely in 1950 as a result of financial constraints.

Work was eventually resumed in 1974 and included the remodelling of the lower section of the deviation between De Doorns and Osplaas as well as the construction of the short twin tunnels.

The tunnel system was opened on 27 November 1989, by which time the Class 4Es were already withdrawn from service after having spent their entire careers double-heading trains across the Hex River rail pass.

[11] Soon after they entered service, Hex River Valley farmers complained that the bottle green livery made the locomotives difficult to see when they were approaching through the vineyards.