Small defects on the rails develop fast under the continuous load of passing trains, and this may lead to train derailment and other disasters. In recent years, many types of wireless sensor systems have been developed for rail defect detection. However, there has been a lack of comprehensive reviews on the working principles, functions, and trade-offs of these wireless sensor systems. Therefore, we provide in this paper a systematic review of recent studies on wireless sensor-based rail defect detection systems from three different perspectives: sensing principles, wireless networks, and power supply. We analyzed and compared six sensing methods to discuss their detection accuracy, detectable types of defects, and their detection efficiency. For wireless networks, we analyzed and compared their application scenarios, the advantages and disadvantages of different network topologies, and the capabilities of different transmission media. From the perspective of power supply, we analyzed and compared different power supply modules in terms of installation and energy harvesting methods, and the amount of energy they can supply. Finally, we offered three suggestions that may inspire the future development of wireless sensor-based rail defect detection systems.

This paper presents a new kind of distributed fault recorder including the design of the system structure, the hardware and software design of the recorder. The recorder adopts NI CompaceRIO series programmable automation controller (PAC) in the hardware while virtual instrument technology in the software. The network communication based on TCP/IP between the client and the server is adopted in the power plant. Moreover, an improved frequency tracking algorithm is presented in the monitoring of the electric quantity to improve the detection precision and the processing speed. The detection and operation results show that it has improved the performance greatly and realized authenticity, integrity and reliability and so on.

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