Abstract: The present invention relates to feeding fabric runs into tenter machines of the kind having lead-in rails adapted for movement to follow lateral deviations of the selvage edge of the fabric and, more particularly, to the drive apparatus for laterally moving the lead-in rails including a reversible driving motor carried by the lead-in rail and a capstan member rotatably driven by the driving motor. A cable member is looped around the capstan member having a first end connected on one side of the rail member and a second end connected on the opposite side of the rail member. A sensor means detects the lateral variations in the position of the selvage edge for generating an electrical signal which is then supplied to the driving motor for reversibly driving the capstan member moving the rail member laterally back and forth according to the lateral position of the selvage edge.