The document includes provisions that apply to the construction, installation, operation, inspection, testing, and maintenance of underhung crane and monorail systems, track sections, and load-carrying members, such as end trucks or carriers (commonly called trolleys) that travel either on the external or internal lower flange of a track section. The track sections include single monorail track, crane bridge girders and jib booms, all curves, switches, transfer devices, and lift and drop sections. Provisions apply to both power-driven and handoperated equipment in which the carriers are independently controlled.