The predecessor of the Blue Train was the Union Limited/Union Express, connecting Johannesburg with Cape Town, and timetabled to meet passenger liner arrivals from the UK. In 1928 the articulated C-22 carriages replaced the balcony stock previously used, and in 1929 the C-21 lounge and observation cars arrived from Belgium.
At this stage, the SAR followed US practice of marshalling lounge cars at the rear of the train and the baggage van at the front, due to the large window and lack of corridor connection at the rear of the lounge car.