Dynamic track stabilization: development of a real-time sensor for measuring lateral sleeper vibrations during operation

This paper presents the development of a camera-based sensor designed to measure lateral vibrations of rail sleepers during Dynamic Track Stabilization (DTS), a critical process for strengthening railway infrastructure by improving track resistance to lateral movement. The DTS unit generates horizontal vibrations perpendicular to the track axis and sets the track grid into controlled small vibrations. At the appropriate vibration frequency, the ballast stones start to move and reorganize into a denser, more uniform structure. The newly developed sensor system employs a high-speed camera to continuously acquire images of railway sleepers as the rail vehicle travels at speeds of up to 5 km/h. This setup enables non-contact measurement of sleeper vibration signals, primarily in the frequency range of approximately 25–45 Hz or higher, with sub-millimeter precision. The method involves analyzing image sequences (based on image phase correlation) to measure small relative displacements caused by the DTS-induced vibrations. The sensor's accuracy was validated through laboratory tests using a laser distance sensor and inductive displacement sensors. Field tests confirmed the sensor's robustness and effectiveness in real-world conditions. The results indicate that the sensor can reliably measure vibration frequencies and amplitudes, providing valuable data for track condition monitoring and predictive maintenance. Overall, this sensor represents a significant advancement in railway maintenance technology, offering a detailed analysis of track stabilization processes and contributing to more efficient and cost-effective railway infrastructure management.