In the old days, grandfather never knew what time he’d have to leave for work. Sometimes, when he was just ready to blow out the kerosene lamp and go to bed, there would be a knock at the door. On the dark porch stood a boy, still panting from a bicycle ride up the street. He was the railroad call boy, and he’d come to say that an engineer was needed right away. Grandfather had been assigned to the job. So he pulled on his clothes and went off, no matter how sleepy he was. [Illustration] [Illustration] The place where Sam leaves his train is called a division point. Other men will take over all the cars of redball freight and speed them on another division of their trip. Let’s see who these different railroaders are and what they do. UNSCRAMBLING THE TRAINS Sixty freight cars have come roaring together over the mountains behind Sam’s engine. But now the cars have to be separated. Some of them are going to Baltimore. Some will turn north to Chicago. Others are bound south. Freight cars for twenty different cities are coupled together in one train, and somebody must unscramble them. Suppose you have a lot of colored beads on a string and you want to separate them into greens and reds and blues. The easiest way is to get three cups and let the beads drop off one by one, each into its own cup with the others of the same color. That’s just what railroaders do with a freight train. Instead of cups, of course, they have a lot of separate tracks, all branching off a main track. On one branch track, they collect the cars that go to Baltimore; on another, the cars for Chicago; on another, the cars headed south. This system of tracks is a classification yard. In order to turn the cars from one track to another, there must be a lot of switches. A switch is made up of movable pieces of rail that guide the cars’ wheels. Look at the picture and you will see how a switch guides a car either along the main track or onto a branch track that curves off to the right. [Illustration] [Illustration] Some of the most wonderful inventions in the world have been put to work in the big freight classification yards. First the regular engine leaves the train and a special switch engine couples on. The engineer of the switch engine has a radio telephone in the cab, so he can listen to orders from the towerman who unscrambles the train. The towerman sits in a tower beside the track at the top of a little hill called the hump. The main track goes over the hump and down. Then it divides into several branch tracks. If you uncouple a car just at the top of the hump, it will roll down the slope by itself. To make the car go onto the right branch, the towerman works an electric switch. He just pushes little handles on the board in front of him, and electric machinery moves the switches in the tracks.