The Lancaster wagon Co built ten vans for the M.R.W.A. in 1891. They were identical in design to those used by the G.S.R., 14'-0" long with an 8'-0" wheelbase and 9'-5" high. They were originally numbered 1B-10B. A further four were built and the whole fourteen vans were renumbered 180-193 (date unknown but after 1901). From 1912 these vans started to be converted to class BM although two (184 and 191) provided parts for BL class vans. Conversion to class BM was completed by 1927. After the conversion the vans were listed as 10'-3" high at the centre of the roof. The class was renumbered BM801-812 in 1932. A new van (813) was added to the class in 1934 by conversion of an HM class horsebox. The diagram below is the WAGR outline diagram for the ex GSR vans.

None ever received W.A.G.R. numbers although it seems that it took the W.A.G.R. some time to catch up with them after the 1964 takeover. Disposal of the class was as follows: 1963 807 written off 1964 804, 806, 809, 810, 812, 813 written off 1965 801, 805, 808, 811 written off 1966 803, 808, 809, 8?? to JETTY 310, 323, 313, 311 1967 802 written off Four BM's became Jetty wagons at Northam. Both the wagon cards and the jetty stock list give BM809 becoming Jetty 313. However, Jetty 311 is also listed as ex BM 809. JETTY 323 went to Boyup Brook in 1967 whilst JETTY 313 went to Narrogin. The bodies are recorded as being removed from all except JETTY 311.   A partial view in the RHWA collection of one of the BMs in service is shown at right.

The MRWA outline diagram for the BM class is shown below.