Where is a gantry girder most used?

1.  The purpose of gantry Girder is to pick and move heavy machinery components within industrial building.
2. A girder is commonly used many times in the building of bridges.
3. Gantry girders are used in workshops/factories for movement of cranes which lifts material and shifts from one location to other.
4. Overhead travelling cranes are used in factories and workshops to lift heavy materials, equipment's, etc. and to carry them from one place to the other.