12, 18" Radius sections are needed to create a circle with a 36" diameter.There is no roadbed track that can match up to the scale-model quality and versatility of Atlas' True-Track. It is easy to assemble and affordably priced, but do not mistake True-Track for a toy. It is a true hobby track system, created for the novice modeler looking not only for realistic appearance but unparalleled performance in a ready-to-run roadbed track. True-Track features Atlas' world-renowned Snap-Track that has been setting the standard for HO track for over 40 years. The piece of Snap-Track can be removed and used separately as desired. For more on how you can use True-Track, please click here. Like all Atlas model railroad products, True-Track adheres to high quality, prototype standards that the hobby world demands. The result is a roadbed track with true-to-prototype gray, graveled roadbed; code 83 brown ties and nickel silver rail correctly angled roadbed shoulder. It looks every bit like real track with roadbed and ballast. 12 18" radius sections are needed to create a circle with a 36" diameter.