The invention relates to a method for controlling the operation of a positioning system (10) of a train, the system (10) including: a toothed tone wheel (12), three sensors (18, 20, 22) for detecting the presence of a tooth, arranged spatially so that six possible and different positions of the wheel (12) may be represented by six possible logic states of the three sensors (18, 20, 22), the six states being different, the method including a step for: detecting states corresponding to the signals delivered by the three sensors (18, 20, 22), comparing the detected states with the values of the six logic states, determining the operating state of the system (10) according to the comparison.