A Smartphone-enabled IoT System for Vibration and Noise Monitoring of Rail Transit

With the development of the urban rail transit system, the ride comfort of trains in operation has been emphasized by passengers and railroad operators alike. The monitoring of interior vibration and noise levels of trains provides an efficient way to guarantee ride comfort. Traditional monitoring equipment has numerous disadvantages, such as high cost, poor mobility, and lack of real-time evaluation functions. To solve these problems, this study explored the utilization of smartphones to measure vibration and noise and diagnose human comfort levels. A smartphone application has been developed based on the Internet of Things (IoT) concept. The smartphone device not only realizes data sensing, visualization, and transmission, but also fulfills edge-computing functions to process sensing data and evaluate vibration and noise impact in real time. The design principle and major components of the developed application are elaborated. In situ experiments were conducted on the Hong Kong Mass Transit Railway, which provides valuable experiences for applying IoT monitoring technology in the rail transit systems and enables the realization of citizen sensing in the future.