This invention is concerned with the elimination of vibration in signature gathering machine delivery chains. Reciprocal motion in some components of a signature gathering system creates periodic forces which may be at or near the natural frequency of the delivery chain. This causes undesired vibration in the chain. The present invention damps this vibration by continuously constraining the lower run of the chain and by placing a positive drive at the tail end sprocket of the chain to take up some of the slack in the return run. The vibration is also substantially reduced at its source by placing a flywheel on the mainline drive shaft near the point where the reciprocal motion is derived.