Long line of coal train cars being rotated and dumped at the power plant in China

From The comments:
"Serously, i was expecting maybe the bottom of the cars to open up and let the coal out but when they started flipping the dam train i just about lost it"

"While hopper cars do have the bottom dump doors, it is not uncommon for them to be rotary dumped, as well, besides the solid bottom coal cars like these. What is required is a rotary coupler at one end of each car. A rotary coupler stays coupled to the adjacent car as it is being dumped. The centerline of the rotary device runs through the couplers. The rotary end of a car is usually painted a color to distinguish it from the non-rotary end. Such a train is usually run from mine to powerplant as a solid unit, never uncoupled (except to remove a car for repair or maintenance). Because the train can be pulled from either end, there is usually a car with two rotary couplers in the train, to put a rotary at the outside ends."

"The concept of dumping train cars like this started in 1880s and still one of the primary methods in America. Cars cost less (very little hardware), empty cars weigh less (no doors, hoppers etc), larger capacity, etc.
The transporting of coal, especially over long distances, is most economical with rotary dump cars and rotary car dumpers. "