Development and Experimental Testing of a 3D Vision System for Railway Freight Wagon Monitoring

Ensuring the safety and reliability of freight wagons requires continuous monitoring of couplings such as hooks and buffers, which are prone to stress, wear, and misalignments. This paper proposes a vision-based 3D monitoring system which uses an RGB-D camera and a computer vision pipeline to estimate angular excursions and longitudinal displacements of wagon couplers during train operation. The proposed approach combines depth-based reconstruction with a normalized cross-correlation tracking algorithm, providing geometric measurements of coupling motion without physical contact. The system architecture integrates real-time acquisition and post-processing analysis to 3D reconstruct the geometric characteristics of wagon couplings under field conditions. Experimental tests performed on a T3000 articulated wagon allowed us to measure an angular excursion of approximately 9.8° for the hook and a longitudinal displacement of 17 mm for the buffer. The results show robustness and suitability for embedded implementation, supporting the adoption of vision-based techniques for safety monitoring in railways.