Gantry cranes are used where overhead runways are not practical or where an overhead crane is not strong enough. Generally gantry cranes are used for moving heavy loads outdoors.
Some more features of gantry cranes include:
Unlike other cranes that are mounted, gantry cranes are moveable.
Gantry cranes can lift tremendous weight, up to five tons.
You can adjust where lifts in terms of adjustable height.