Abstract: At present, the main maintenance mode of the component parts of railway contact network in China is manual overhaul under power outage, which both time and labor consuming.With the rapid development of the construction of electrified railway in China, the total mileage of the railway has increased, it is more and more important to improve the repair efficiency of contacting parts.Therefore, analyzed the actual situation of the network maintenance work, and designed an unmanned contact network maintenance vehicle.The vehicle can be equipped with test equipment according to the actual needs of users and achieve automatic positioning parking in the distance from the center of the column of the contact net ±20 mm through the BDS receiver positioning function, then change the position of YZ coordinate platform automatically and make the equipment reach the predetermined position, and detect the parts of the contact network.The PLC is used as the slave computer in the control system of the vehicle to control the various parts of the maintenance vehicle, through the wire or wireless communication mode.A industrial computer is used as the upper computer in the control system of the vehicle, on the one hand, which realize the function call of the lower computer, on the other hand, which could analyze and process the data from the BDS receiver and testing instruments, which achieve automatic positioning of unmanned vehicle maintenance, so as to realize the automatic detection of the component parts of railway contact network.

Key words: contact network, BDS, PLC, automatic positioning