Interest in double trolleys appears to be increasing again, but there are other, less expensive ways to improve cycle times.
Improving crane cycle times is becoming an increasingly difficult challenge. It is generally agreed that there is little point in pushing hoist/lower speed beyond 90180 m/min (laden/unladen) and trolley speed much beyond 240 m/min. ZPMC has delivered an experimental crane to Waigaoqiao with a trolley speed of 350 m/min and SSA has specified 300m/min for two cranes for a terminal in the USbut these are very much the exceptions which prove the rule....
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Approx 2750 words from WorldCargo News, December 2002,
page 49.
