Abstract：As China's rail transit network continues to expand in scale and operational speed, the service safety and structural reliability of key components of trains and tracks shows increasingly high requirements on the accuracy, depth, and non-destructive nature of damage examination technologies. Traditional analytical methods struggle to achieve real-time and dynamic tracking of microstructural features inside materials and components. In contrast, synchrotron radiation X-ray and neutron methods are advanced and powerful characterization tools in modern material detection fields. They have acted a crucial role in assessing internal damage in large metal components due to their unique and outstanding advantages such as high brightness, high resolution, and strong penetration capability. This paper systematically reviews the fundamental principles, classifications, and key characteristics of synchrotron radiation and neutron technique. To be more specific, this paper mainly focuses on their recent studies and applications in modern railway materials and components, particularly in composition and microstructure, residual stress measurement, and in situ monitoring of internal defects and fatigue evolution behaviors. It includes the application progress of microstructure characterization of structural materials, residual stress measurement of the wheels, axles and rails, as well as in situ tracking of internal defects and fatigue properties of lightweight materials, etc. While this paper primarily targets mature materials such as alloy steels, it also briefly surveys novel structural materials including titanium alloys, magnesium alloys, and carbon fiber composites. Furthermore, this paper demonstrates the advantages of in situ three-dimensional imaging in capturing the dynamic evolution of defects and neutron diffraction in characterizing the deep residual stress of large-scale components. Collectively, these findings provide key data support for the research and development of advanced rail transit materials, production process optimization and safety assessment under service conditions. Finally, the study outlines the core and practical development direction of promising future in this field, and serves as a vital reference and scientific basis for the further application of non-destructive characterization technology in the railway field.
2026, Vol. 47 
