WO type iron ore waggon WO 31251 is one of a batch of eighty six built by WAGR Midland Workshops between 1967 and March 1968 with fleet number 140 for Koolyanobbing iron ore operations, with a 75 ton and 1018 ft³ capacity, empty train arriving at Binduli Triangle, 31st July 2010. This unit was converted to WOC for coal in 1986 till 1990 when it was reclassed to WOG for gypsum, then it was re-classed back to WO in 1994.