A never-ending stream of coal flows by various rail routes from our coal mines to our seaports and lake-ports. At these ports the coal is loaded into steam vessels—some for reshipment to American ports, some for export to foreign lands, some to fuel the ships that carry on our sea-borne commerce.

At many of these ports, the railroads own and operate great coal storage yards large enough to hold thousands of coal cars at one time. To stand on a bridge or other elevation and look out over one of these huge yards with its acres and acres of cars laden with coal is a sight one will never forget.

But the most impressive spectacle of all at one of these coal terminals is the towering mechanism by which the coal is unleaded from the cars into the holds of the ships. Some railway coal terminals are equipped with two or three coal dumping machines, each capable of unloading from 40 to 60 cars an hour.

Described by one writer as "an inspiring spectacle of engineering wizardry," the electrically-operated mechanical unloader, similar to the one in the picture, grips the largest coal car, fully loaded, lifts it 50 to 75 feet or more above the track structure, dumps its contents into the coal "pan" leading to the ship's hold, and returns the car to its original position. Some unloading machines are capable of performing all of these things in less than a minute.

By this method a ship of 10,000 tons capacity can be loaded in two and one-half hours.

Ocean-going ships engaged in coal trade have an average capacity of about 5,000 tons, although there are some which carry upwards of 10,000 tons. Some of the coal-carrying vessels on the Great Lakes range from 10,000 to 15,000 tons capacity.

A carload of coal comes from the mines, perhaps hundreds of miles away, on a regular waybill. When the car arrives at the port terminal, the waybill is checked by yard clerks, and the car is switched to a track containing cars loaded with a similar grade or brand of coal. The number of the car is recorded on sheets held by the yardmaster and the coal pier offices.

Now, suppose a ship has just arrived at the port to be loaded with this particular grade of coal. The yardmaster issues instructions to a yard crew to deliver this and other cars containing the same grade of coal to the gravity load yard, or "barney yard." There a crew releases the cars as they are wanted for unloading. When released the car drifts by gravity down the tack to the scales where it is weighed automatically. The weight is checked by the sale clerk and transmitted by "telautograph" to the office on the pier, where the car number and weight is checked again before dumping. Then a narrow-gauge electric locomotive, known as a "barney," or "mule," moves the car up the incline track to the unloader. When it is in its proper position beneath the steel structure it is gripped firmly by the giant unloading machine, lifted up to the "pan," turned over as easily as a boy would turn a glass of milk, dumped, and set back on the track, where it rolls off by gravity and comes to a halt in the empty yard. When dumped into the "pan," the coal slides down a huge adjustable telescopic chute into the hold of the ship.

At some coal piers cars are lifted by elevators to tracks 50 or 75 feet or more above the pier floors and dumped into "pans" through hoppers in the bottoms of the cars. Piers equipped for handling cars in this manner sometimes have several chutes enabling several cars to be "spotted" and dumped at the same time and enabling two or more vessels to be loaded simultaneously.

While the work of transferring coal from cars to ships is in progress on the pier, a staff of checkers and office workers are busy keeping tally sheets and records of coal in the yard, coal moved to unloaders, coal dumped, coal on the way from the mines, coal stored, coal classified, coal weighed, empty cars returned, demurrage charges, and so on.

Controlling the movement of the coal from the gravity yard to the ship's hold are several operators who maintain constant communication with each other by telephone, loudspeakers and push-button signals.

Car dumping machinery of this kind is also used for loading ores, sand and gravel, sulphur, and other heavy bulk commodities into vessels.