Lowbed semi-trailers, also called “lowboys,” are designed for loading and hauling heavy equipment. Hauling capacity ranges from 40 to 50 tons or more. They are used to haul crawler tractors, excavators, large rubber-tired tractors, and other heavy machines. Lowbed trailers are designed for loading and unloading under field conditions and several types are available. The large trucks that pull these trailers are equipped with heavy-duty winches to assist in loading. A fifth-wheel kingpin, located under the front platform or gooseneck, joins the trailer to the truck. Many goosenecks fold down or detach from the trailer bed to facilitate loading and unloading. The gooseneck is then repositioned and locked in place for transport. Caution should be exercised when dealing with heavy equipment to prevent injury as well as proper attachment (“booming”) of equipment to the trailer to prevent accidents. Special hauling permits may be required, especially for oversized loads.