An in-depot realtime train tracking system using RFID and wireless mesh networks

Knowing the real-time position of moving trains is critical for public transportation safety. To obtain the real-time train position, signal based, video based and sensor based solutions have been proposed. However, those solutions are either too expensive or only applicable for normal driving scenario. In this paper, we propose a real-time tracking solution for light railway trains inside the depot to avoid potential collisions. The system utilizes RFID technology to localize trains' current position and sends the position information to control center using wireless mesh networks. The proposed solution is low cost and easy to deploy on both railway and train side. We designed RFID deployment strategy to improve the sensor reading accuracy. In addition, we proposed a Bloom filter based communication protocol to transmit the RFID reading, which can effectively eliminate network packet loss / RFID duplicated reading and other errors. Based on the location information, we designed two sample applications and deployed them in real train depot. Extensive on-site experiments have been conducted to show the effectiveness of the system.