Something does rise up like fingers from the sides of the track. It is the car retarder which squeezes against the wheels and keeps the car from rolling along too fast.
The retarder works by electricity. The towerman just presses a button or a handle in the tower, and far down the track the retarder machinery goes to work. Before railroads had this machinery, brakemen went over the hump with the cars, working fast and hard to put the hand brakes on at just the right time. Brakemen who did this were called hump riders.
Once in a while a hump rider still goes with a car of very fragile freight that might be broken if it banged into another car the least bit too hard.
Car after car drifts down the hump and stops just where it should. When one freight train has been unscrambled, another rolls up beneath the tower, and its cars, too, are shuffled. In just a few hours half a dozen trains have been broken up and made into new ones.
Some yards have extra inspectors who stand on top of a building and look down at the cars from above. They can see broken parts that the man in the inspection pit might miss. In other yards, a man is stationed beside the track that leads up to the hump. In his hands, he holds something that looks like a gun. It is—an oil gun. As each car passes, he takes aim and fires a stream of oil straight into the car’s journal box. (You’ll read about the journal box on [page 42].)
Not every freight yard has a hump or car retarders or radio telephones. Only the biggest ones have all these things. In many yards the switch engine pushes the whole train first onto one track and then onto another, dropping a car each time.
There are several kinds of switch engine, built especially for their jobs. But switching is often done with very old engines that aren’t fast enough for regular runs any more. Railroad men call an old wheezy engine a teakettle. An ordinary switch engine is a bobtail or a yard goat.