The Type YE1 tender entered service in 1904, as tenders to the second batch of four Karoo Class 4-6-2 Pacific type steam locomotives of the Cape Government Railways, which would be designated Class 5B on the South African Railways in 1912.

[1] The Cape Government Railways (CGR) placed four more Karoo Class steam locomotives with a 4-6-2 Pacific type wheel arrangement in service in 1904.

[1][2][3] The Type YE1 tender had a coal capacity of 6 long tons (6.1 tonnes), a water capacity of 2,825 imperial gallons (12,800 litres) and an average maximum axle loading of 11 long tons 6 hundredweight 3 quarters (11,520 kilograms).

The tender had the same dimensions and water capacity as the Type YE tender, but a 10 long hundredweight (0.5 tonnes) bigger coal capacity and a 6 inches (152 millimetres) longer wheelbase.

[3] A number, when added after the letter code, indicates differences between similar tender types, such as function, wheelbase or coal bunker capacity.