The Type YB tender entered service in 1893, as tenders to the first 6th Class 4-6-0 Tenwheeler type steam locomotives to be acquired by the Cape Government Railways.

[1] The Cape Government Railways (CGR) placed its first forty 6th Class 4-6-0 Tenwheeler type steam locomotives in service in 1893 and 1894.

[1][2][3] The Type YB entered service as tenders to these locomotives, which were distributed between the Western and Midland Systems of the CGR.

In 1912, these locomotives were designated Class 6 on the South African Railways (SAR).

[1][2][3] The tender had a coal capacity of 5 long tons 10 hundredweight (5.6 tonnes), a water capacity of 2,370 imperial gallons (10,800 litres) and an average maximum axle load of 9 long tons 17 hundredweight (10,010 kilograms).