are overlapped and form a means for checking each other where there is overlap the control system of the present invention includes an electrical connection 22 for controlling the actuation or application of auxiliary eddy current brake 19 and an electrical connection 24 for controlling the actuation or application of the brake band of primary friction brake 13 a conventional signal processor 18 which is typically a general purpose digital computer includes a control program represented by the flow diagram of fig2 to produce an output control signal on electrical connection 22 fig1 to control the application of auxiliary brake 19 when the hook block position and or the speed of the hook block reach predetermined levels more specifically processor 18 calculates from the load signal appearing on output line 20 and from the speed signal appearing on output line 23 a braking value that is applied to the traveling hook block to reduce the speed to the desired level for the position of the block at any given time should the calculated braking value speed for the position value exceed a predetermined level processor 18 produces a control output 24 to actuate primary band brake 13 the upward movement of the hook block is usually controlled by the application of a floor pedal shown in fig1 or a hand control by the driller the processor also takes over the control of the throttle to reduce the throttle when.