Abstract: Apparatus embodying the invention includes first and second motors coupled to a carriage assembly for moving the carriage assembly back and forth between first and second end points. The first motor is for developing a force to drive the carriage in one direction and the second motor is for developing a force to drive the carriage in an opposite, second direction. When the first motor causes the movement of the carriage in one direction, the slowing, stopping and reversal of the carriage is achieved by varying the power supplied to the second motor relative to the power supplied to the first motor until the force exerted by the second motor first equals and then exceeds the force exerted by the second motor. So operated, the carriage motion is well controlled and exhibits little, if any, backlash.