West Kalgoorlie, WOB type iron ore waggon WOB 31390 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 315 for Koolyanobbing iron ore operations and is one of the 15 converted to WSM type ballast hoppers by re-fitting the removed top section of the body and fitting bottom discharge doors. Converted back to WOB in 1997, fleet number not yet applied and having been fully re-sheeted and painted with the new angled lip applied to the top of the body.