Unloading machinery empties the cars in many places, too. There’s one coal yard where a woman, pushing buttons, controls machines that do everything—unload cars, store the coal according to its size in tall bins, and load the trucks that will deliver it to customers. This is how the yard works:
Each railroad car empties its coal in a stream onto a moving belt. The belt carries the coal to a machine called a giraffe, which works like an escalator. The giraffe lifts the coal into a tall hopper.
The woman who runs the coal yard sits in an office with a big window, where she can look out and see everything that’s going on. When a truck has backed up to a hopper, ready to load, she pushes a button. Coal drops down out of the hopper onto another giraffe which lifts it into the body of the truck. As soon as the truck is filled, push goes a button and the loading stops.
LOADERS, LIFTERS AND SUCH
Moving belt machines work at other jobs, too. They load sand into trucks and cargo into ships.
On some piers, huge vacuum cleaners empty ships full of sugar or wheat. At ports on the Great Lakes, machines reach down into ore-carrying ships and unload them with great speed. At the end of each of these unloaders hangs a clamshell bucket. Just above the bucket is a little room where a man sits and watches what goes on. He signals to the operator, telling him just where to drop the bucket so it can pick up a mouthful of ore. The ship can be unloaded by two men who do nothing but signal to each other and push levers. But usually there are several machines working at the same time so that the job goes as quickly as possible.
When iron ore has been turned into steel bars or wheels or gears, another kind of lifter can handle them. This one does its work with a huge electro-magnet that holds heavy weights when electricity is running through it. The operator drops the magnet onto the load of iron or steel that he wants to lift. Then he turns on the electricity which makes the magnet and the piece of metal stick together. The operator moves the load wherever it is supposed to go. Then he turns off the electricity. The magnet lets loose and is ready for another job.