Each section combines track and roadbed into a single unit, 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. A great system for Christmas, displays or permanent layouts. Twelve sections of curved 18" radius track make a full circle; 16 sections of curved 22" radius track make a full circle.