Features Two per package Dimensions Length 10" track section 6 1/4" wide road section. Track curves are measured from CENTER RAIL TO CENTER RAIL. The actual area the track takes up is a few inches more to include the track bed. O-31 Curves need 8 curve track pieces for a complete circle – Approximate area will be 3 feet O-36 Curves need 8 curve track pieces for a complete circle - Approximate area will be 3.5 feet O-48 Curves need 12 curve track pieces for a complete circle - Approximate area will be 4.5 feet O-60 Curves need 16 curve track pieces for a complete circle - Approximate area will be 5.5 feet O-72 Curves need 16 curve track pieces for a complete circle - Approximate area will be 6.5 feet O-84 Curves need 32 curve track pieces for a complete circle- Approximate area will be 7.5 feet O-96 Curves need 32 curve track pieces for a complete circle- Approximate area will be 8.5 feet