Abstract: Disclosed is a control system for maintaining the linear alignment of end-coupled, adjacent sections of self-propelled sprinkler irrigation apparatus, and for interrupting power to the drive means when any adjacent sections are in gross linear misalignment uncorrectable by the control system. A magnetic reed switch and permanent magnet combination, together with a metallic shield interposed between them, act as alignment sensors and overtravel sensors to open or close the reed switch in accordance with the alignment status of the irrigation system. A logic circuit utilizing an exclusive OR-gate is disclosed which causes the function of the alignment control sensors to reverse whenever the direction of the irrigation apparatus reverses, and, also, an electronic circuit utilizing a digital capacitance meter to indicate which tower is in gross linear misalignment, if any, should the apparatus automatically shut down.