The Bachmann Graduated Pier Set makes it easy to create an over-and-under figure "8" layout or similar configurations. Compatible only with E-Z Track sections, the clearance under the tallest piers is 3-1/8" 7.9cm - tall enough for most HO trains to roll underneath. Whether for your first train set or for more advanced layouts Bachmann HO Scale E-Z Track makes setting up easy. Each section combines track and roadbed into a single piece, with snap-fit assembly and plug-in wiring to provide instant railroad fun. A hidden locking feature holds sections securely together until you're ready to take them apart. Easy to set up on any surface, including floors and rugs, no special tools, nails or boards are needed. Steel-alloy rail is easy to keep clean and corrosion free with normal indoor use. Molded black roadbed is used on steel alloy track and is fully compatible with gray-roadbed nickel silver track. A great track system for Christmas displays or permanent layouts. As reference, 12 sections of curved 18" radius track make a full circle; 16 sections of curved 22" radius track make a full circle.