In 1953 a total of thirty RB class open wagons were rebuilt as flat wagons and reclassified QRB. This is another one of those classes that should by rights have gone into the U class group. 749, 779, 784, 828, 1901, 2735, 3094, 3234, 4050, 4288, 11179, 11182,11184, 11203, 11205, 11206, 11220, 11225, 11232, 11236, 11239, 11244, 11245, 11272, 11278, 11281, 11292, 11301, 11303 ex RB In 1968 most of the class (749, 779, 784, 828, 1901, 3094, 3234, 4050, 11182, 11184, 11203, 11205, 11206, 11225, 11232, 11236, 11244, 11245, 11272, 11278, 11292, 11301) were fitted with bolsters for pipes and reclassified QRP, although three wagons (3094, 11272, 11301) were reconverted back to QRB the same year. At some point 835 was fitted to carry a ballast plough but this was later removed and in 1972 the wagon became the QRJ class tank wagon (another misclassification - this should have been a J something).  The remainder of the class were disposed of as follows

The WAGR outline diagram is shown below.