Energy self-contained freight train monitoring system with cooperative wind and vibration energy harvesting

The dynamic nature of freight train formations and the lack of onboard power infrastructure pose significant challenges for condition monitoring. Deploying sensors in energy-scarce locations is impractical, limiting networked monitoring capabilities. Consequently, there is an urgent need to develop methods for harnessing ambient energy during operation, thereby enabling an energy self-contained monitoring system. This paper proposed a cooperative energy harvester system that captures both wind and vibration energy to power autonomous condition monitoring modules. The hybrid configuration employs a wind harvester and a vibration converter to transform mechanical energy from train motion and track-induced oscillations into electrical power. Experimental evaluation yields peak outputs of 40.87 mW at an airflow velocity of 10 m/s and 26.21 mW at a vibration frequency of 20 Hz with a 5 mm amplitude. Under continuous operation, the storage unit reaches full charge in 20 h via wind harvesting and in 45 h via vibration harvesting under a wind speed of 10 m/s and a vibration frequency of 20 Hz with an amplitude of 5 mm, while simultaneously sustaining the sensing module. The results indicate that the proposed system can harness multiple ambient energy sources to deliver stable and continuous power under variable conditions, making it a promising solution for renewable energy-powered freight train monitoring applications.