How Hydraulic Cranes Work
Heavy rains spawned by Hurricane Danny flooded many parts of Charlotte, NC. Flood waters rose so quickly in Little Sugar Creek that the underpinnings of a train trestle collapsed, bringing a diesel locomotive crashing down into the creek. As you might imagine, a 412,000-pound (186,880-kg) locomotive is not easily lifted. After the waters receded, emergency teams brought in three large hydraulic truck cranes -- one 500-ton, one 300-ton and one 175-ton -- to lift the train out of the creek bed and back onto the train tracks.Hydraulic Crane Image GalleryHydraulic truck cranes can lift thousands of pounds using the simple concept of transmitting forces from point to point through a fluid. See more hydraulic crane pictures.Hydraulic cranes are very simple by design but can perform Herculean tasks that would otherwise seem impossible. In a matter of minutes, these machines are able to raise multi-ton bridge beams on highways, heavy equipment in factories and even lift beachfront houses onto pilings. Hydraulic truck cranes are also used to lift killer whales like Shamu out of water tanks when places like Sea World ship the whales to new destinations.When watching a hydraulic truck crane in action, it's hard to believe just how much weight it's moving because it deals with these multi-ton objects with relative ease. Hydraulic truck cranes vary in lifting power. It's easy to tell how much a particular hydraulic truck crane can lift just by the name of it: A 40-ton crane can lift 40 tons (80,000 lb or 36,287 kg).In this edition of HowStuffWorks, you will learn how these cranes are able to lift thousands of pounds using hydraulics, and we'll climb into the cab to show you just how these machines are operated.