A gantry crane is a type of overhead crane with supports that hold it up that are fixed in location. This means that the crane cannot move, so everything that it is going to lift must be brought to the crane. The supports form a large rectangular frame upon which the crane can move forward and back, and left and right. Anything that can be reached by the gantry crane is referred to as being in its operating area.
These cranes are very common in factories, where they are used to move things along the factory floor as the product is slowly assembled. For instance, if a company is building a large metal piece of equipment, the metal parts may arrive on a truck. The truck will park within the operating area of the crane, which can then be used to unload the parts. The crane may also be used to move the parts around, typically along the assembly line as the components are assembled. Once the item is complete, the crane can be used to load the finished part back onto a truck so that it can be removed from the factory.
Since a gantry crane can be used to lift very heavy weights, the operator must receive special training in its proper operation and lifting techniques. In some places, it may even be necessary to have an operating license.
Every crane is designed to be able to lift only a certain maximum amount, and that weight should not be exceeded. Moving a heavy weight on the end of a long cable can also provide unique challenges that the operator must be aware of and know how to handle.