PURPOSE: To facilitate the management of an overhead wire and the decision of the existence of the repairing of the overhead wire, by judging the state of the flaw of the overhead wire while traveling in a self-travel way on the overhead wire, and by storing the read data in a memory medium together with the data of a rotary counter, and further, by enabling respectively the read-out of the data, the judgment of the state of the damage of the overhead wire and the storage of the data on the ground.

CONSTITUTION: According to a travel starting command from a ground transmitter 50, a car-borne equipment suspended on an overhead wire starts self-traveling. Then, the introductions of the signal from a part 10 for sensing the flaw of the overhead wire and the signal from a rotary pulse sensor 37 for sensing the position of the flaw on the aerial wire are performed. When there is any flaw on the overhead wire, an amplitude signal data and the data of a rotary pulse counter are stored in a memory in succession. Further, a control part 20 for storing these data in a removable memory medium is provided. Since in such a manner the car-borne equipment can be made to travel and stop on the overhead wire by the ground transmitter 50, flaws on the overhead wire can be sensed accurately. Also, since the sensed data are stored in the removable type memory medium, the detection data can be analyzed easily on the ground.