The National Energy Technology Laboratory of the US Department of Energy (under Award DE-FC26-02NT41645) and the NYSEARCH Committee of the Northeast Gas Association (previous the New York Gas Group), have sponsored research to develop a robotic pipeline inspection system capable of navigation through the typical physical and operational obstacles that make transmission and distribution pipelines unpiggable. The research contractors, Foster-Miller and GE Oil & Gas (PII North America) have performed an engineering study and developed a conceptual design that meets all the requirements for navigating and inspecting unpiggable transmission pipelines. Based on Foster-Miller's previous efforts developing the Pipe Mouse robot, the RoboScan inspection robot (Figure ES-1) meets the navigational and physical challenges of unpiggable pipelines through an innovative modular platform design, segmented MFL inspection modules and improvements to the inter-module coupling design.