A 'mobile straddle lift gantry crane' will run on which of the following?

• A. Jib
• B. Rails
• C. Rubber tires
• D. None of the above

Answer: (C)

The key idea here is how a mobile gantry crane moves. A mobile straddle lift gantry crane is designed to travel on wheels—specifically rubber tires—so it can reposition itself around a work area. It isn’t mounted on rails, and its lifting arm is the bridge with a hoist between the legs that straddle the load. The term “straddle” refers to the legs that go around the load, not the method of movement.

Rubber tires are what allow this crane to move like a mobile piece of equipment in a yard or shop floor, whereas rails would indicate a fixed track system. A jib is a separate horizontal arm typical of jib cranes, not the mobility system of a gantry crane.