The Railways and Harbours Brigade was formed in 1901 as the Imperial Military Railway Volunteer Corps, which after the Anglo-Boer War became the South African Railways Volunteer Corps. In 1906 it was once again changed, this time to Central South African Railways Engineer Corps (C.S.A.R.E.C.). In 1912 it was incorprated in the Transvaal Cycle and Motor Corps, which subsequently became the R.L.I. In 1916 it was reformed as the Railways and Harbours Rifles, consisting of two battalions formed from the personnel of the two departments, which by 1920 became the Railways and Harbours Brigade, also operating two armoured trains. Disbanded in 1926, it was resuscitated again in 1940, and the establishment was increased to eleven units which included Railways Operating, Dock Operating, Workshops, Signals, Artillery and Armoured Car Units, Railway Construction, Harbour Construction, Survey and other units. With the re-constitution of the Active Citizen Force after the War, the Brigade was retained and consisted of five battalions, trained in infantry and engineering tasks.

Semper Paratus - Always Ready