In the current Trains Magazine, is a photo and report of a run by BHP Iron Ore, of a train that was four and a half miles long, weighing 109,705 tons It was powered by all eight of BHP's GE AC6000 units, spread throughout the train in DP mode. A new world record for the longest and heaviest train!
The mind boggles on how one discharges all that ore? At the Pt Augusta Power Station I have been led to believe that they completely rotate the coal wagons upside down in a cradle without disconnecting them from the train. The grain trains I work with are far less sophisticated with bottom opening valves. Each of our largest wagons takes approximately 4 - 5 minutes to discharge. Imagine how long it takes BHP.
If the cars do have rotating couplers as they do in the USA with coal gons, the unloading can be quite quick, but it is a L-O-N-G train to empty