Atlas is the leading manufacturer of model railroad track, worldwide. You will find that our track is easy to use and will last on your layout for years. All Atlas code 100 track is made with premium nickel silver rail and black railroad ties." 12 Pieces are needed to complete a circle. (Note: Radius is always measured to the center of the rails.) WARNING: CHOKING HAZARD - SMALL PARTS! NOT INTENDED FOR CHILDREN UNDER 3.