Untethered, remotely-controlled robot for inspecting live underground natural gas distribution pipelines. The battery-powered Explorer can perform long-range, extended duration visual inspections of cast-iron and steel gas mains. Unlike older, tethered systems, Explorer can inspect thousands of feet of pipeline from a single excavation point. An operator controls Explorer through a wireless link and can monitor pipeline images in real time. Each locomotor has its own camera, the system and provides views at either end to allow observation during travel in both directions. The image management system allows for the operator to observe either of the two views or both of them simultaneously on his or her screen.