rear end hydraulic system in reference to whatever may be the instantaneous manual positioning of arm 235 governing operation of the front end hydraulic system it will be appreciated that cabling for practice of the invention can take a variety of forms depending on the desired relation between piston 26 displacement and z axis displacement of the load two fold four fold and 8 fold multiplications of piston 26 displacement are achieved depending upon the number of frame referenced versus piston referenced sheave passes are provided for each of the cables for example a two fold multiplication 1 2 ratio of piston retraction for load lift displacement as shown in fig3 is typical for a yard container crane where the range of z axis positions is about 20 feet on the other hand for handling container freight which must be placed and removed from the hold of a container ship a vertical displaceability range of 160 feet is possible with traction cylinders 25 25 39 providing a 20 foot range of actuation using a 1 8 cabling and sheave configuration since for simplicity fig3 dealt only with pure lift z axis considerations the cables 29 30 29 39 30 39 are shown to end with direct ties to the load 10 this is of course to have omitted consideration of y axis accommodation however in fig2 both ends of each of these cables are secured to the frame of.