Dr. Yunlong Guo is a Marie Skłodowska-Curie Research Fellow at the University of Birmingham, United Kingdom. He earned his PhD in Civil Engineering from Delft University of Technology. His research specializes in railway geotechnics and railway structure monitoring, employing advanced methodologies such as digital twins and machine learning.Dr. Guoqing Jing is a Professor at the Highway and Railway Engineering Department at Beijing Jiaotong University, China. He received his PhD in Civil Engineering from INSA de Rennes, France. Previously, he served as the Vice Director of the State Key Laboratory of Waterproof Materials in China and as a Guest Professor at UMP, Malaysia. Professor Jing’s current research focuses on ballasted track engineering, with an emphasis on recycled and composite materials. His work extensively utilizes numerical methods such as the discrete element method.

• 1. Ballast and ballasted track2. Ballast material selection and evaluation3. Special structures4. Geotechnical laboratory test on ballast5. Sleeper‐ballast interactions (lateral resistance)6. Sleeper‐ballast interaction (longitudinal resistance)7. Sleeper‐ballast interaction (vertical stiffness)8. Rail and management9. Recycled materials of railway sleeper10. Smart railway sleeper11. Composite materials of ballasted track12. Image analysis for ballast13. Discrete element method application14. Polyurethane reinforced ballasted track15. Ballast flight16. Drainage17. Inspection Robots18. Maintenance and management19. Railway ballast fouling‐mechanism, inspection and solutions20. Developing trend and perspectives