Cranes are industrial tools that are used to raise and lower heavy items. Gantry cranes and jib cranes are among the most used in factories for a number of reasons. Jib cranes are cheaper to build and maintain but they are not as versatile as gantry cranes. Gantry cranes are big and expensive but move items anywhere on a factory floor.
The most obvious difference between a gantry crane and a jib crane is their anchoring. The jib crane uses a single pole for it's anchor while the gantry crane uses steel runners. The steel runners could be mounted on a loading tower or along the sides of a factory ceiling.
The gantry crane is able to support much heavier loads due to its greater support. The jib crane only has a single pole that is bolted into the ground. Too much weight and the pole can torque out of the ground by shearing the bolts in half. Gantry cranes can have enclosed steel runners that grip the top and bottom of their wheels, thus holding them in place.
Range of Movement
A gantry crane is much more maneuverable than a jib crane. The jib crane can only rotate about it's pole and slide the crane winch back and forth along the supporting beam. However a gantry crane can slide back and forth along it's runners and side to side on the supporting beam. Ship-building dockyards use gantry cranes because they can change position easily, carrying prebuilt sections from the factory to the dry dock.
Jib cranes are most commonly used to move smaller loads a short distance. For example, the crane on the front of a barn is a jib crane -- all it has to do is swing out and raise hay bundles up to the second floor. Gantry cranes are used in factories, power plants, shipyards and seaports. Gantry cranes are used for heavy objects moved long distances and over other things.