Building An Airplane a jet airplane is one of the fastest machines on the planet. But have you ever seen one being made? It all goes together like a jigsaw puzzle! Once it's assembled, a test pilot takes the jet out for a flight. Will it pass the test? Soon the jet is ready to get to work flying people all over the world. Ride the Mountain Rails! Work train is busy keeping the tracks in good shape. It takes the power of three engines to get up the sharp inclines and over the pass. These machines are a special hardy breed, made for the mountain ride. Reach for the Sky Stretch is a crane and his job is to lift things onto the top of very high buildings. He's attached to a truck so he can drive to jobs. But he's so tall that he has to be taken apart in order to fit through the streets. It takes a friend, Yellow Crane, to help stretch assemble again!