Ballast particles are an important part of the railway ballast bed. Ballast particles with irregular shapes and strong randomness are not only of significance for ensuring track stability, but also provide good elasticity to absorb the impact and vibration of wheel–rail interaction. However, it is obviously unrealistic to import the contour of every real ballast particle when using the discrete element method (DEM) simulation. Therefore, this paper developed a new algorithm, the random midpoint displacement method (RMDM), for the fast reconstruction and random generation of 2D ballast particle contour. Seven morphological parameters are proposed to describe the surface characteristics of ballast particles based on the analysis of the contour samples of three typical ballast particles using MATLAB. This method was verified by comparison with the real ballast particle based on particle morphology analysis and DEM simulation. The results show that the reconstructed ballast contour by RMDM is consistent with the field ballast contours in the view of the fractal dimensions and has an improvement in the view of the computational efficiency.

Current research on the vibration characteristics of fastener clips primarily employs modal experiments combined with finite element simulations; however, limited attention has been given to the dynamic vibration behavior of clips during actual train operations. This study investigates both the quasi-static and dynamic vibration characteristics using an integrated approach of finite element simulation and dynamic testing. Based on the Vossloh W300-1 fastener system, a three-dimensional model is established. Modal and frequency response analyses, together with field test validation, reveal two significant vibration modes within 0–1000 Hz: a first-order mode at 500 Hz and a second-order mode at 560 Hz. These modes are characterized by vertical overturning of the clip arm. Dynamic testing demonstrates that the dominant frequency of the arm acceleration is strongly correlated with the second-order natural frequency, confirming that wheel–rail excitation readily triggers second-order mode resonance. The study further shows that, at train speeds of 200–350 km/h, rail corrugation with wavelengths of 99.2–173.6 mm induces high-frequency excitation at 560 Hz, resulting in resonance fatigue of the clip. As a mitigation measure, regular rail grinding is recommended to eliminate corrugation at critical wavelengths. Additionally, optimizing the clip structure to avoid resonance frequency bands is proposed. These findings elucidate the coupling mechanism between the vibration characteristics of the clip and dynamic loads, providing theoretical support for the safety evaluation of high-speed rail fastener systems and the vibration-resistant design of clips.

Rail transit, as the artery of the national economy, an important national infrastructure and a popular means of transportation, is the backbone of the comprehensive transportation system, featuring energy conservation, environmental protection, safety and large transport capacity, plays a crucial role in China’s economic development. With the rapid development of rail transit, the number, level and structure of personnel demand of railway transportation system will change significantly, and the existing rail engineering can no longer adapt to the new railway personnel demand. This paper investigates the training mode and teaching content of railway transportation department personnel through questionnaire. The results show that the existing talent training mode is weak in practice, the teaching content and methods are not suitable for training technical application-oriented talents, the teaching methods are backward, and the experimental and practical training equipment is insufficient. Some suggestions are put forward to construct competency-based curriculum content system and strengthen the construction of experimental and practical training base.