The R class reflected an ongoing evolution of VR locomotive design and a response to the changing operational environment of the VR in the postwar era.

The R class adopted the bar frame construction of the H and S class express passenger locomotives, which had proven to be far more robust in coping with the VR's varying track quality than the fracture-prone plate frames of the A2.

The decision to install MB Type 1 mechanical stoker equipment (capable of feeding up to 10,000 lb (4,536 kg) of coal per hour)  on a locomotive with only a 42-square-foot (3.9 m²) grate reflected improved postwar working conditions for locomotive firemen, the varying quality of postwar coal  and the expectation of sustained high speed operation of the locomotive.
The manually fired prewar VR S class Pacific, although capable of 2,300 drawbar horsepower (1,700 kW), was limited by the physical ability of the fireman to feed its 50-square-foot (4.6 m²) grate and as such was reliant on coal with a high calorific value.

Online locomotive database steamlocomotive.com notes: "They showed an interesting blend of European, British, American, and Australian practice.
The slotted pilot is Australian, the long sand dome American, the Belpaire firebox and cab British, and the mid-line smoke lifters ('elephant ears') European."

Other modern features included SKF roller bearings on all axles and the innovative, lightweight SCOA-P type driving wheels, which were specially developed for the R class by the Steel Company of Australia.
The R class reflected an ongoing evolution of VR locomotive design and a response to the changing operational environment of the VR in the postwar era.
The R class adopted the bar frame construction of the H and S class express passenger locomotives, which had proven to be far more robust in coping with the VR's varying track quality than the fracture-prone plate frames of the A2.
The decision to install MB Type 1 mechanical stoker equipment (capable of feeding up to 10,000 lb (4,536 kg) of coal per hour)  on a locomotive with only a 42-square-foot (3.9 m²) grate reflected improved postwar working conditions for locomotive firemen, the varying quality of postwar coal  and the expectation of sustained high speed operation of the locomotive. The manually fired prewar VR S class Pacific, although capable of 2,300 drawbar horsepower (1,700 kW), was limited by the physical ability of the fireman to feed its 50-square-foot (4.6 m²) grate and as such was reliant on coal with a high calorific value.
Online locomotive database steamlocomotive.com notes: "They showed an interesting blend of European, British, American, and Australian practice. The slotted pilot is Australian, the long sand dome American, the Belpaire firebox and cab British, and the mid-line smoke lifters ('elephant ears') European."
Other modern features included SKF roller bearings on all axles and the innovative, lightweight SCOA-P type driving wheels, which were specially developed for the R class by the Steel Company of Australia.
Victorian Railways R class