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This study presents the validation of a dynamic test system to simulate a high‐speed train passing bridges under seismic excitation. The system comprises scaled models of a CRH380A high‐speed train and an 11‐span simply supported bridge on a shake table array. This innovative apparatus combines seismic loading with the moving train load to replicate train‐track‐bridge interaction (TTBI) during earthquakes. It allows investigation of various train speeds and seismic excitations, providing invaluable insights into TTBI. First, the detailed similarity design principle based on the equations of motion was discussed, and its applicability to the wheel‐rail contact relationship was verified. Then, the dynamic characteristics of the scaled model were identified, and the impact of the error between the scaled model and the theoretical model on the TTBI response was assessed. Furthermore, the comparison of the dynamic test model and the numerical simulation in acceleration responses validated the accuracy of the rigid‐flexible coupling model method for the actual TTBI system. Test cases without external excitation, with simple harmonic excitation and with seismic excitation were conducted on the dynamic test system. Results showed that the influence of track irregularity and running speed on train response aligns with the classical train‐bridge interaction theory. The successful implementation of this test system marks a significant advance in understanding TTBI mechanics and has significant implications for seismic safety enhancement of railway infrastructure. [ABSTRACT FROM AUTHOR]

The derailment of a high‐speed train is a complex and uncertain dynamic process, especially under running conditions where the derailment index lacks comprehensive experimental validation. This research focuses on elucidating the mechanism of an earthquake‐induced train derailment and validating the structural response‐based spectrum intensity derailment index. To achieve this, a multi‐array shaking table system was utilized to test the safety of a running train and to physically replicate train derailment process under severe earthquake impact. We investigated the vibration characteristics and derailment progression of trains operating at different speeds, exposed to earthquakes of varying frequencies and intensities. In stationary derailments, significant wheelset lift was observed due to lateral rolling vibrations. However, in running test cases, there was no separation between the wheels and rails. Instead, the wheels underwent a long period of climbing and descending on the rails, similar to damped single‐degree‐of‐freedom oscillations. As the wheel climbed the rail and reached a critical potential energy point, the wheel flange of the wheel could potentially fall due to gravity or come off the rail due to external disturbances. The critical potential energy could be represented by the spectrum intensity threshold, and the prediction results aligned well with the derailment test results for both stationary and running trains. Furthermore, the method of determining train derailment based on structural responses was consistent with the test results. The spectrum intensity index shows strong positive correlations with other wheel‐force‐related indicators, albeit adopting a conservative perspective, reinforcing its efficacy in assessing train safety. [ABSTRACT FROM AUTHOR]

The pulse effect of near-fault ground motion has asevere threat to high-speed railway train running on bridge. Current research generally relies on numerical simulation and lacks physical test data. In this paper, a scale indoor physical test of high-speed train running on bridge is conducted and dynamic characteristics of high-speed railway train–track–bridge system under near-fault pulse-type ground motion are explored. The bridge of the physical test is excited by shaking table with lateral inputs of near-fault pulse-type ground motion, pulse-free ground motion and far-field ground motion. A corresponding numerical model is established and validated by the test data. Then, the influence regularities of pulse effect on system dynamic response and running safety indexes are explored under different peak ground acceleration (PGA) and train speeds using data of the physical tests and the numerical simulation comprehensively. Results suggest that compared to the near-fault pulse-free ground motion and the far-field ground motion, the near-fault pulse-type ground motion leads to larger lateral beam displacement, lateral train acceleration, and running safety indexes in different degrees. And from the data results of this paper, its lateral wheel–rail force and derailment coefficient are the first to break through the limit values. By studying the parameter sensitivity of lateral train acceleration, it was found that under the near-fault pulse-type ground motion, the lateral train acceleration is significantly more sensitive to changes of train speed and PGA. From the perspective of energy, the near-fault pulse-type ground motion results in spectrum intensity (SI) indexes which are larger and improve faster with the increase of PGA than other ground motions. This indicates that it inputs significantly more energy into the high-speed railway train–track–bridge system, although it may not excite larger lateral beam acceleration. [ABSTRACT FROM AUTHOR]

This paper aims to address the problems of safety and durability in China's ballastless track structures, particularly the lack of accurate analysis and methods for predicting the reliability of the new type of prefabricated track structure during the design phase. We propose a reliability prediction method for a new prefabricated track structure, the modular assembled track structure with built-in position retention. By adopting the fuzzy Failure Modes, Effects, and Criticality Analysis (fuzzy FMECA) method, a comprehensive assessment of fault severity, fault occurrence probability, and fault detection difficulty is conducted on the CRTS II slab track structure and the modular assembled track structure with built-in position retention. Consequently, a fault mode hazard assessment model for the new prefabricated track structure is constructed. Based on the assessment model and using a similar product method, a reliability prediction model for the new prefabricated track structure is established, and reliability prediction for the track structure is conducted. The research results indicate that the modular assembled track structure with built-in position retention has lower hazard levels and higher reliability compared to the CRTS II slab track structure. This study provides a scientific basis for the design optimization of new prefabricated track structures, helping to improve their safety and reliability, reduce operating and maintenance costs, and thereby promote the green and low-carbon development of the railway. [ABSTRACT FROM AUTHOR]