4 foot section straight track. Matthews does not recommend that the two types of track be used together. The chrome plating used on the Heavy Wall can create size buildup and the finished diameter may be slightly larger. This can create a noticeable "bump" at the joint. Matthews curved tracks are available to complete 10', 20', and 70' diameter circles. Be advised that most dollies will not navigate the 10' circle without the addition of a multi-wheeled device such as the Matthews Centipede #395200. Four pieces of 90 degree curve track are needed to complete a circle. Eight pieces are required for 20' diameter and 16 pieces for the 70' diameter circle. All Matthews Dolly Track is rated to a maximum payload of 1200 lbs (545kg) at the industry standard of 24.5 center to center track width. SPECIAL NOTE: To insure against damage to the product during transit, all Curve Dolly Track must be crated prior to shipment. Please allow 2 working days from receipt of order for crating. Matthews will not be responsible for track shipped without crating.