The R Class are diesel locomotives built by English Electric, Rocklea for the Western Australian Government Railways in 1968. They were followed by the revised RA class.

The R class were a hood type general purpose diesel-electric locomotive. They were similar to the Queensland Railways 1300 class. All equipment, except traction motors, were interchangeable with the standard gauge K class. The bogies are an English Electric design with low weight transfer characteristics. They feature fully equalised primary spring gear, all traction motors in each bogie mounted with the nose-suspension facing inwards, traction thrust at near axle level and long pivot centres to reduce inter-bogie transfer. Adhesion loss at maximum tractive effort is limited to 4.5 per cent allowing 1,830 long tons (1,860 t; 2,050 short tons) trailing load to be hauled up a 1 in 100 grade.^[1]

In 1968 the Western Australian Government Railways took delivery of five narrow gauge versions of the K class for use on bauxite traffic, the last three being fitted with 6 tonnes (5.9 long tons; 6.6 short tons) of ballast to improve their tractive effort. All were fitted with dynamic brakes.^[2][3][4]