A method and an arrangement for operating a storage and retrieval unit (3) are specified. A rail line (1) respectively a power supply rail (6) for the storage and retrieval unit (3) is set to a risk mode voltage, the rectified value/effective value of which lies below a minimum rectified value/minimum effective value necessary to move the storage and retrieval unit (3) but above zero, if a risk posed by the storage and retrieval unit (3) is detected. Alternatively or in addition, the voltage applied to the rail line (1)/power supply rail (6) can also be investigated in the storage and retrieval unit (3) for modulated change signals. The applied voltage is passed on to a traction motor (5) of the storage and retrieval unit (3) only when it has been established that the normal operation-traction voltage and not the risk mode voltage has been applied to the rail line (1)/power supply rail (6).