Heavy-duty facilities classified according to FEM STANDARDS in class M6 (3m) - M7 (4m) - M8 (5m) for mechanisms and A6-A7-A8 for structures. They are designed and built for intense use and high flow rates, sizing is established based on the intended use. The lifting unit, wheel units, blocks etc. are specifically designed for the service they are intended for in order to obtain adequate performance and facilitate any maintenance operations. Special bridge cranes can be equipped with specific under-hook equipment such as sling bars, magnets, suction cups, hydraulic or mechanical buckets, electronic systems for acceleration and speed control, weighing systems, and can be operated from the ground or from the cab.