The Auxiliary Trolley, compatible with LightRail 3.5 and 4.0, has many uses. First, it is the same Trolley, minus hardware, as what is packaged with the Add a Lamp Hardware and the same Trolley that you would find in the Add-A-Lamp Kit. In addition to using it to move a second light as part of the Add-A-Lamp Kit, it can also be used to aid in the festooning or tying with a bungie, any vent tubing and grow light cords. In this instance, as your Motor goes along in one direction, it gently pushes ductwork or cords out in front and as your Motor goes along in the other direction, it gently pulls ductwork or cords along behind. The LightRail Auxiliary Trolley is sold on its own, as shown, to provide available extra Trolleys and can be used for a variety of purposes.