WO type iron ore waggon WO 31248 is one of a batch of eighty six built by WAGR Midland Workshops between 1967 and March 1968 with fleet number 139 for Koolyanobbing iron ore operations, with a 75 ton and 1018 ft³ capacity, loaded with fines seen here at Bonnie Vale, 28th May 2006. This unit was converted to WOG for gypsum in late 1980s till 1990 then reclassed to WOS for superphosphate before being re-classed back to WO in 1994.