The present invention provides a long-range, untethered, live, in-pipe inspection system that includes a self-propelled train having a plurality of modules; joint members for interconnecting adjacent modules, data collection components, and wireless communication components for transmitting collected data and receiving control messages. The module-train includes, generally, at least one, and preferably two drive modules, at least one power module and an electronics module. The train may additionally include at least one support module, which may be interposed between the power and electronics modules. In one embodiment of the invention, there are two drive modules, one at each terminal end of the train, two power modules, one adjacent to each drive module, two support modules, one adjacent to each power module, and one central electronics and computing module.