[1][2][3] Type XJ tenders were built by the North British Locomotive Company in 1911.

[1][2][3] The Cape Government Railways (CGR) placed two 4-8-2 Mountain type steam locomotives in service in 1911, designed by CGR Chief Locomotive Superintendent H.M. Beatty at the Salt River works in Cape Town.

These locomotives were designated Class 4 on the South African Railways (SAR) in 1912.

[1][2][3] The tender had a coal capacity of 6 long tons 10 hundredweight (6.6 tonnes), a water capacity of 3,500 imperial gallons (15,900 litres) and a maximum axle load of 10 long tons 19 hundredweight (11,130 kilograms).

[3][4] Only the two Class 4 locomotives were delivered new with Type XJ tenders, which were numbered 1477 and 1478 for their engines.