conveyor system accessories are disclosed , which provide an inexpensive way to stage , stockpile and / or sort work pieces and provides easy entry to and exit from a main conveyor . in particular , a trolley or trolleys that carry work pieces ride on the conveyor rail above the chain or intermesh with the chain on the inside of the track . these accessories are used with single track continuous conveyor systems , which greatly enhances the productivity of the single track system by permitting work pieces to be taken off - line without taking the work piece off a load pendant .