This paper presents a design of a tracked in-pipe inspection mobile robot with a flexible drive positioning system. The robot is intended to operate in circular and rectangular pipes and ducts oriented horizontally and vertically. The paper covers the complete design process of a virtual prototype, focusing on track adaptation to the working environment. A mathematical description of kinematics and dynamics of the robot is presented. Operation in pipes with a cross section over 210 mm is discussed. Laboratory tests of the utilized tracks are included, confirming conducted FEA simulations.