Sensing solutions for assessing and monitoring high-speed railroads

Railway turnouts are critical subsystems in railway lines guiding trains to correct directions. Due to the heavy traffic load and highly irregular and complicated profile of rail tracks at railway turnout zones, fatigue cracks can easily occur both at the rail surface and inside the rail structure that subject to long-term cyclic loading and impacts of passing trains. This issue is particularly risky in high-speed railway systems, and real-time monitoring and assessment of the rail condition at turnout zones are essential. Taking advantage of ultrasonic sensing techniques and their wide applications in railway sector, this chapter introduces a rail condition assessment scheme based on passive ultrasonic measuring, i.e., acoustic emission method from sensor development and pilot lab investigation to in situ measurement with the whole set of structural health monitoring system. By incorporating the state-of-the-art data-driven algorithms, the method is able to provide quantitative evaluation for in-service rail tracks.