WOB type iron ore waggon WOB 31399 is one of a batch of twenty five built by Comeng WA between 1974 and 1975 and converted from Mt Newman high sided waggons by WAGR Midland Workshops with a capacity of 67 tons with fleet number 323 for Koolyanobbing iron ore operations, empty train arriving at Binduli Triangle, 31st July 2010.