A take-up rail assembly including a fixed idler rail and a longitudinally movable take-up rail. The fixed idler rail is attached to a quilting frame or other sewing frame and the position of the fixed idler rail may be longitudinally and vertically adjustable with respect to the sewing frame. The take-up rail is movably attached to the sewing frame and a take-up rail control mechanism moves the take up rail longitudinally forward and rearward with respect to the fixed idler rail as the sewing machine moves with respect to the sewing frame, thus providing full utilization of the throat length of the sewing machine.