A rack is a straight or flat gear, and is used with a gear pinion. (See Spur Gears). If one was to take a circumference of a round gear, unfold it, then lay it flat it would be a rack. A rack and pinion produces a linear movement in any plane. If the rack is fixed and the pinion rotates whatever is attached to the pinion will drive along the rack.
LMR can cut racks onto most sections of material and has designated plant for this process. Long sections of Rack can be joined together by feeding the material through the machine.