Railway ballast fouling, inspection, and solutions - A review

Ballast fouling occurs when the voids of granular particles are wholly or partially filled by fine particles. Railway ballast fouling is always an inevitable issue related to railway performance and safety in ballasted tracks. This paper presents an overview of the railway ballast fouling mechanism, current works, perspective, and innovation. The paper first reviews the fouling mechanism with different fouling sources and their influence, followed by the fouling indices. Then, fouling inspection methods are reviewed, and the ground penetrating radar is highlighted due to its high efficiency and accuracy. The proposed solutions, including rehabilitation, prevention, reinforcement, and stabilization in the ballasted track, are introduced. Additionally, several perspectives and works for the future are mentioned. Ballast cleaning is a thorough and effective treatment. Ground-penetrating radar inspection and proper evaluation can provide a preview and perspective on ballast cleaning determination.