In 1913/4 the M.R.W.A. either acquired or built 5 bogie open wagons. They were similar to the W.A.G.R. R class and could indeed have been W.A.G.R. wagons 683, 1595, 1600, 1654 and 1749 which are known to have gone from W.A.G.R. stock before June 1909. The M.R.W.A. may have purchased these wagons from a third party such as the PWD as the diagram below shows them to be 9" longer than a WAGR R class. They were numbered 7 (1913), 8-10, 17 (1914). In 1931 these wagons were renumbered 81-85 but not in the same order. It is known that 81 was 9 and 85 had been 17. In 1953-5 they were again renumbered. This time to 861-865. In 1950-3 another group of W.A.G.R. R class wagons on loan became L1018, 1020-8, 1068-70 for a short period.

In 1957 862 and 863 were rebuilt followed by 861, 864, 865 in 1958. These rebuilds had a body that was essentially two WAGR GE class (MRWA AE) wagons stuck together as seen in the RHWA collection image above. A further two of this type (866, 867) were built in 1963 using salvaged bogies and other parts. In 1964 numbers 861, 863 became W.A.G.R. RB40711, 40713 whilst 862, 864, 866, 867 became RBM 40712, 40714, 40716, 40717. Number 865 became RBM 40715 in 1965 when 40711, 40713 were also reclassified RBM. In 1973 this group were all reclassified RAM. Numbers 40712, 40714, 40715, 40717 were all written off in 1978 followed by 40713 in 1980 and 40711, 40716 in 1983.