The train/railcar(s) is accurately positioned onto the dumper platen. The remaining railcars in the string are held in place with a holding device. As the dumper barrel rotates on the centreline axis of the railcar couplers, car clamps securely hold the railcar in place during rotation. The material is unloaded into the hopper and is transported via a conveyor located under the hopper. The barrel rotates to its original position as the car clamps are raised. The next railcar(s) in the train is (are) indexed into position, and the cycle repeats.