1) Box girder crane
An overhead traveling crane that utilizes a "box" configuration in fabricating the bridge girder. This box girder design incorporates a four-sided box with a running surface plate for the hoist trolley attached to the bottom of the box. The advantage of the box girder is that it possesses greater loading capabilities and is able to span greater bridge distances. Generally utilized in pairs with the hoisting mechanism operating on rails attached to the top of each box girder.