Giant Crawler Cranes...

Typical crane operation requires the weight of the lifted load and that of the boom to be stabilized by the weight of the body of the machine. The fulcrum is located near the center of the track below the boom. Stabilizing moments must be greater than overturning moments. A moment is a force or weight multiplied by the applicable distance from the fulcrum. The wind, which can topple the crane forward, must also be considered.

Giant crawler cranes dramatically demonstrate the principles of classical mechanics. These powerful machines are essentially fulcrums that counterbalance the outstretched boom and the lifted load with massive machinery, a heavy chassis and counterweights.

Since their introduction around the 1920s, crawler cranes, who's name refers to their "track-type tractor tread" have improved continually. The newest generation uses very high strength steel to reduce boom weight, remote sensing devices and microprocessors to thwart overloading, and high-pressure hydrostatic drives to achieve precise motion control. Such technology notwithstanding, today's giant crawler cranes work essentially the same way that their ancestors did, by exploiting the rules of equilibrium and mechanical advantage.

Safe crane operation requires careful adherence to engineered guidelines made complicated by the shifting of the overall center of mass of the equipment and factors such as the length and position of the boom, counterweights, accessories in use, and the lifted load... in addition to the the wind.