Motorized Single-Girder Cranes
The wheels on top running overhead bridge crane operate on either ASCE crane rail, square or rectangular rail. They tend to have a longer wheel and bearing life expectancy than underhung cranes of the same type and capacity.
A top-running overhead bridge crane offers excellent headroom advantages over other styles of cranes due to the extra lift height that is gained by having the crane girder on top of the end trucks rather than suspended from the bottom of the trucks as in underhung applications.
A top running single girder overhead bridge crane that requires spans to exceed 60 to 65 ft. is likely to be a box girder constructed crane. Box girder bridge cranes have a very light weight to span ratio and in many cases can reduce the size of the runway and building structure required to support them. These cranes are often referred to as mono box bridge cranes.
CMAA Class C is standard but an overhead bridge crane is available inclassess A-D. To decide which class meets your application needs refer to CMAA Classifications.