Cost-effective railway solutions: bearing and wheel sensors

Our roads and flyovers are already crowded with vehicles, so we need to turn to another transportation solution: rail. This shift has played a major role in driving the rail industry to improve infrastructure and maintenance processes. Therefore, approximately 25% to 35% of train operating expenses are used for track maintenance needs. What is needed is a cost-effective rail solution. The need for solutions that optimize jobs in the rail industry is becoming more and more important. These solutions will help find defects in the early stages of development, allowing operators to fix damage before it becomes severe. When a vehicle is scheduled for repair or overhaul, understanding damage and severity is beneficial, reducing operational issues, optimizing fleet availability, and reducing overall loss and disruption costs. Mechanical Sensors One of the solutions implemented is mechanical sensors. These sensors are used to measure track geometry. Before the introduction of ultrasonic transducers in railway inspection in 1953, electromagnetic technology was one of the main tools for detecting internal defects in railways in high-speed railway networks. Since then, various inspection methods have been used to monitor the health of rail infrastructure or as a measure to prevent rail failures. Track bearings and wheels are an important part of a train; any defect can have serious consequences. Premature failure of rail axle bearings can lead to significant increases in train operating costs and can affect train safety. A healthy bearing will generate some level of vibration and noise, but a defective bearing will generate considerable vibration and noise levels. Likewise, wheel defects on railway wagons have been identified as a significant source of damage to railway infrastructure and rolling stock. They also cause noise and vibration emissions, which are costly to mitigate. Defects in railway vehicle wheels directly contribute to the increase in wear and damage to railway infrastructure. As a result, this increases additional costs for maintenance and repairs, thereby shortening the life and availability of rolling stock. Early detection of train wheel defects plays an important role in providing train operators with timely information on necessary repairs, which can prevent further wheel deterioration and further damage to railway infrastructure. Over the past few decades, with the help of data-driven railways, there has been an increased focus on the quality of measurement technology used to support decision-making in the railway sector. Traditionally, high-precision inspections have been carried out against established standards, or where inspections are impractical, periodic actions have been used to support safety-based decision-making within the railway. While safety remains a top priority, maintenance decisions have received increasing attention. Condition monitoring systems are designed to identify the condition of an asset and inform the decision-making process. As a result, this helps reduce the incidence of urgent and costly unplanned interventions, thereby improving performance and safety. Sensing Technologies Different sensing technologies monitor axlebox bearings and wheels, such as vibration/acceleration, microphone/sound measurement, acoustic emission/ultrasonic and thermal. Vibration, sound measurement and ultrasonic techniques are used to detect early defects. Thermal sensors, on the other hand, are based on detecting the heat generated by severely defective bearings and wheels. Rail operators have raised the need for more cost-effective and environmentally friendly solutions. This has led to many technologies being integrated into the sensor itself to reduce additional costs. For example, new sensors on the market are based on vibrational energy harvesting technology within piezoelectric PVDF materials, which is environmentally friendly and low-cost. The technology, combined with a sensor design, utilizes piezoelectric PVDF materials to convert vibrations into electricity. The technology is based on a cantilever structure, and when the cantilever vibrates, the electrical energy it produces is stored in a supercapacitor. After that, the electricity from the capacitor is delivered to the sensor. In conclusion, the current market places special demands on the railway industry, leading to an increased demand for cost-effective and safety-oriented solutions. Rail axle bearings and wheel sensors play an important role in detecting early defects that can lead to serious consequences. Energy harvesting technologies also play a role in saving money and the environment.