5 Tough Trucks

World Book's Learning Ladders Tough Trucks

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Bulldozer A bulldozer is the first truck to arrive at a construction site. This tough truck pushes huge piles of rocks and dirt out of the way. It clears the ground quickly, so people can build new roads and houses. A bulldozer's sharp prongs break up hard, rocky ground. Caterpillar tracks roll easily over the rocks and soil. The cab has thick windows to protect the driver from the noise of the clattering engine.

Smoke from the engine puffs out of a long exhaust pipe. A metal blade pushes the heavy piles of rocks and dirt out of the way. It's a fact! This bulldozer works underwater! It is clearing a ditch so that pipes can be laid.

Crane A crane lifts a heavy object high above your head. The crane can turn and reach and put the object in a different place. It can put a pipe into a deep hole or on top of a tall building! This crane is lifting a big pipe that is hanging from wires. A hook grips the wires firmly. A pipe is a heavy load. It's a fact! A crane lifts objects with its long arm. This crane's arm can stretch across a football field!

A crane's arm is called a boom. The boom can move up and down and from side to side, and it can stretch near or far. A crane driver works the boom. Giant feet, called jacks, stop the crane from toppling over. Tall cranes stand in a line at this busy port. They lift big boxes onto and off of ships.