In 1953 a total of thirty RB class open wagons were rebuilt as flat wagons and reclassified QRB. 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  Three wagons (3094, 11272, 11301) were reconverted back to QRB the same year. QRP class wagons were written off as follows:

1978	11245 written off
1979	11236, 11278, 11292 written off
1980	784, 11244 written off
1981	11232 written off
1982	749, 11206 written off
1986	11205 written off
1987	11184, 11203, 11225 written off
1988	4050 written off
1990	779, 828, 1901, 3234, 11182 written off