Length, Width, Clearance
  1. The maximum overall width (including wheels and axles) shall not exceed 2 3/4 inches.  
  2. The minimum width between the wheels shall be 1 3/4 inches so the car will clear the center guide strip on the track. 
  3. The minimum clearance between the bottom of the car and the track surface shall be 3/8 inch so the car will clear the center guide strip on the track. 
  4. The maximum overall length shall not exceed 7 inches.