position a 20 ft load rear position 34 and a 20 ft load front position 35 is shown cas can position the chassis for put down at front center or rear but the cas has to know where on the chassis to put the container position selector 21 fig8 a selects between front centre and rear similarly fig9 b shows examples for load positions on a 45 ft chassis the figure shows a spreader position 30 a pick up measure point 31 and a measure point at put down 15 a 45 ft centre load 36 and a 40 ft centre load 37 are shown a 40 ft rear load rear position 38 and a 40 ft load front position 39 are shown cas normally positions the 40 ft container to the same center position as the 45 ft container because the 40 ft spreader can hold a 45 ft or 40 ft container a 40 ft container can with the u201c position selector u201d 21 be placed at front middle or rear the absolute position of the container position at the chassis of front middle and rear can vary between container sizes 20 40 and 45 ft and vary between the three types of chassis the position of the measurement point at the rear of the chassis 15 will of course also vary between the three types of chassis the chassis alignment system cas 6 gets the job orders from the crane control system the job order is given in different ways depending on manual or automatic operation elc the order and the start of measurement is made from the normal operation of the crane i e the.