I’ve never thought about how coal actually gets used. It came out of the ground, it goes into a power plant, soot comes out, and West Virginia dies happy and very, very early. The end. Sure, it had to go onto a train at some point, and that train was probably unloaded by Dickensian street urchins with shovels or something. “A penny for some coal, guv’nah?” they’d say. But no. It turns out they just tip the whole thing over.

This is what’s known as a “rotary car dumper,” and it’s a system that’s been around for over a century, largely with the aim of replacing an even older system. No, not coal-smeared orphans, but a hopper system in which the bottom of the rail car itself would open up:

And while that’s certainly efficient and simple, there are some advantages that “tipping the whole shebang over” brings, as rotary system manufacturer Heyl & Patterson explains on its website:

Unloading of coal at a power plant is much more streamlined with a rotary dumper, also known as a wagon tippler, than with other types of dumpers. The railcar is held in place inside the dumper with clamps, and the entire mechanism rotates so that the car is nearly upside down. This design feature eliminates the waste associated with bottom dump railcars for several reasons. First, the sloping bottoms of traditional hoppers can leave some coal inside the railcar even after unloading, usually due to clumped or frozen material. Second, bottom dump railcars have the potential to spill their contents onto the tracks, especially if there are any imperfections in the seals of the doors. Third, bottom dump railcars often have a more lengthy process of unloading for the previous two reasons.

With rotary-coupled cars, loads can be dumped without unhooking the railcars from one another, which is a system referred to as unit-train. As long as the cars are equipped with rotary shaft tight lock couplings, then the dumper rotates the cars on the axis of the couplers. Two railcars at a time can be dumped in this manner in a tandem dumper. Heyl & Patterson Rotary Railcar Dumpers can unload a car in as little as 35 seconds and dump as much as 5,000 tons per hour, or as much as 10,000 tons per hour in tandem configuration. This machine is simple and user-friendly, and takes only one operator to maintain total control.

Heyl & Patterson goes on to say that the problems with the typical hopper system can be even worse if the coal gets wet and then all freezes together, in which case the coal itself has to be pre-warmed.

But another advantage that Heyl & Patterson is it’s just sort of hypnotizing to watch in action:

Soon this entire industry will be dead, completely replaced by wind, solar, and tidal power, but wind turbines aren’t nearly as fun to tip over. All that gets you is “arrested” for “property damage.”


When that day comes maybe we can all turn these into amusement park rides.

h/t to r/videos