Seventy R class Hudson tender locomotives, the only class of this configuration in Australia and built by North British Locomotive Company, were introduced by the Victorian Railways in 1951 for mainline express passenger operations. However, the introduction in 1952 of the B class diesel-electric locomotives saw the R class almost immediately being relegated to secondary passenger and freight use, with many being staged at depots around the state. A number were preserved and some of these continued to operate on special excursion trains.