This study aims to design and validate an emergency response method for high-speed railway earthquake early warning (EEW) systems based on the Propagation of Local Undamped Motion (PLUM) principle in order to enhance the timeliness and accuracy of warnings under seismic threats.

A hierarchical architecture of the railway EEW system was adopted, in which self-built stations along the railway serve as the backbone and the national seismic network provides supplementary data. Warning zones were designed along the railway using overlapping trapezoidal layouts to cover seismic stations and reduce inter-regional time delays. Offline replay experiments were conducted using 82 historical earthquake events and records from 61 seismic stations to evaluate the timeliness and accuracy of warning information.

The results indicate that the PLUM-based early warning method can issue emergency response information before destructive seismic waves arrive. Multiple earthquake experiments demonstrated high reliability and stability, with effective detection across different magnitudes and epicentral distances. Furthermore, the trapezoidal overlapping zone design improved regional consistency and significantly reduced missed alerts.

This work represents the first systematic application of the PLUM method to high-speed railway EEW in China. By integrating railway operational requirements, the proposed method provides a practical and robust emergency response strategy, offering new insights into seismic risk mitigation for China's high-speed railways.

Type-120 relief valves are critical components of locomotive braking systems, and they rapidly discharge the air pressure during brake release to enable swift pressure relief. In order to develop type-120 relief valve rubber diaphragms with long life and high performance, the damaged faulty samples were analyzed and studied.

Finite element analysis (FEA) was used to investigate the stress distribution and failure mechanism of the rubber diaphragms within the type-120 relief valves under dynamic loading conditions. The Ogden hyperelastic constitutive model was used to fit the diaphragm data obtained from the uniaxial tensile tests, and its suitability for the modeling of large deformations was confirmed.

The FEA results indicated that, when the rubber diaphragms reached their maximum deformation, the peak stress on their upper surfaces was 5.44 MPa. Thus, this region is highly susceptible to fatigue damage. The service life of the rubber diaphragms could be extended by using rubber compounds with high tensile moduli or a fabric-reinforced rubber diaphragm.

This study provides valuable data and experience for the development of the rubber diaphragms in the type-120 valves and other long-life rubber products in the railway field.

For the commonly used concrete mix for railway tunnel linings, concrete model specimens were made, and springback and core drilling tests were conducted at different ages. The springback strength was measured to the compressive strength of the core sample with a diameter of 100mm and a height-to-diameter ratio of 1:1. By comparing the measured strength values, the relationship between the measured values under different strength measurement methods was analyzed.

A comparative test of the core drilling method and the rebound method was conducted on the side walls of tunnel linings in some under-construction railways to study the feasibility of the rebound method in engineering quality supervision and inspection.

Tests showed that the rebound strength was positively correlated with the core drill strength. The core drill test strength was significantly higher than the rebound test strength, and the strength still increased after 56 days of age. The rebound method is suitable for the general survey of concrete strength during the construction process and is not suitable for direct supervision and inspection.

By studying the correlation of test strength of tunnel lining concrete using two methods, the differences in test results of different methods are proposed to provide a reference for the test and evaluation of tunnel lining strength in railway engineering.

This study aims to carry out optimization and improvement work on the artificial climate aging and ultraviolet aging tests of elastic expansion joints in railway concrete bridges.

Three polyurethane elastomer specimens with different chemical compositions were adopted. According to relevant standard regulations, the aging test process was analyzed and evaluated in detail, and reasonable improvement suggestions were put forward. The effectiveness was verified through actual tests.

The final test results indicate that the combination of artificial climate aging tests and ultraviolet aging tests is technically feasible and has significant advantages in practical applications.

This study optimizes the conditions of artificial climate aging and ultraviolet aging tests, compares the advantages and disadvantages of different aging test methods, and proposes a combined test scheme of artificial climate aging and ultraviolet aging and verifies its effectiveness. The results provide valuable reference for simulating the actual aging behavior of polyurethane elastomers, material performance evaluation, and application in railway bridge engineering. It is conducive to promoting the reasonable application of this material in engineering, improving engineering quality, reducing costs, and has economic and social benefits.

Regarding that Ultraviolet radiation, pollutant adsorption, and environmental changes may be the main reasons for the aging and yellowing on windshield rubber in high-speed trains, countermeasures are proposed to solve the aging and yellowing of windshield rubber and reduce the adverse effects caused by rubber yellowing.

Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to test the yellowed windshield rubber. Aging tests, including UVaging, natural aging and salt spray aging, were conducted to analyze the effects of aging on the windshield rubber. Different cleaning agents were selected to soak the windshield rubber, and the quality, hardness, and surface appearance of the rubber samples were tested.

After UV aging, antioxidants migrated to the surface of the windshield rubber, but due to oxidation failure, they could not capture free radicals, leading to continued oxidation reactions within the material and resulting in yellowing of the rubber in a short period of time.

Cleaning agents have a minimal impact on windshield rubber, UV aging has the greatest impact and natural aging is a gradual and slow deterioration process. Through daily deep cleaning and maintenance with protective agents at regular intervals, the deterioration of windshield rubber yellowing in high-speed trains can be effectively suppressed.

To address the encapsulation challenge of fiber Bragg grating (FBG) sensors in complex railway environments, this paper designs a clip-on composite sensor enabling installation-friendly deployment and long-term axle counting system monitoring.

Wheel-rail mechanical behavior was simulated via finite element analysis (FEA) to determine optimal sensor placement. A clip-on composite sensor was subsequently engineered. Stress transduction efficacy was validated through FEA quantification of stress responses at the axle counter location. Findings - The proposed FBG axle counter integrates temperature compensation and anti-detachment monitoring as well as advantages such as simplified installation with minimal maintenance and sustained operational reliability. It effectively transmits stress, yielding a measured strain of 39 μe under static loading conditions without sensitivity-enhancing elements.

This study performs FEA of wheel-rail stress distribution and engineers the dual-slot composite sensor, FEAwas conducted to quantify the stress magnitude at the axle sensor position of the dual-slot composite sensor. Additionally, FEA was performed on sensors with different structural configurations, including adjustments to the axle sensor position, number of slots and axle position. The results confirmed that the designed composite sensor exhibits superior stress transfer characteristics.

This paper focuses on studying the reliability allocation for the railway system, aiming to improve the overall reliability of the railway system and ensure safety operation.

In view of the complex structure of the railway system, involving many subsystems, this paper analyzes the close dynamic coupling effect between railway subsystems. Based on this, taking the railway system failure as the top event, a fault tree is constructed in this paper. Then, a reliability allocation method based on the fault tree is employed to allocate the reliability index. Finally, a numerical experiment is implemented to show the performance of the reliability allocation method.

The results showed that each subsystem needs to improve its reliability to meet the specified railway system reliability requirements, and the traction power supply system is the most important subsystem, which is the most efficient in improving the reliability of the railway system.

For the first time, starting from a holistic perspective of the system, reliability allocation is carried out based on the importance of each railway subsystem.

This research aims to investigate how the adhesion performance of GFRP composite components, commonly used in railway vehicles, is affected when bonded to cataphoresis coated steel substrate surfaces.

In this context, the aim was to determine the optimal adhesion parameters for bonding GFRP samples with natural and primed surfaces to steel samples with cataphoresis coatings. Then, single-lap joint samples with different bond thicknesses of 1 mm, 2 mm and 3 mm were prepared. Finally, tensile tests were performed on the samples.

The results showed that GFRP specimens with natural surfaces, characterised by the highest surface roughness, exhibited the lowest bond strength. But, the highest bonding performance was achieved in specimens where primed GFRP was bonded to cataphoresis coated steel, especially with a bond thickness of 1 mm, and achieving a yield strength of 20 MPa. This situation explains the characteristic difference between surface roughness and chemical coating, which are two essential pre-treatments in adhesive bonding. While surface roughness provides mechanical interlocking, excessive roughness can hinder the adhesive's wetting ability, causing it to remain suspended on the surface as described in the Cassie-Baxter theorem. In contrast, it has been observed that, despite low surface roughness, chemical coatings enhance the bonding between primer paint and adhesive molecules, and - as stated in the Wenzel theorem - improve the surface wettability.

As a preliminary preparation in the adhesive method, primer paint is applied to steel surfaces and GFRP material surfaces in classical industrial applications. In this research, the application of the catapheresis process to the steel substrate instead of primer paint and the bonding of primer-painted GFRP materials to this surface make a unique contribution to the research.

This study aims to implement condition monitoring for urban rail train permanent magnet synchronous motors and inverter systems. Through the construction of a digital twin model, it performs fault diagnosis of potential system failures, enabling rapid fault localization and protection.

This research begins with a brief introduction to the structure and classification of permanent magnet synchronous motors (PMSMs), followed by a detailed analysis of their mathematical model. Subsequently, it thoroughly investigates the working principle of three-phase two-level inverters and the distribution of space voltage vectors. Based on the analysis of the main circuit topology, a digital twin model matching the external characteristics of the physical circuit is established using the model predictive control method, achieving accurate system simulation. Furthermore, through theoretical analysis and simulation verification of phase current characteristics under inverter switch tube faults, general patterns of phase currents under fault conditions are summarized. The established digital twin model is then employed to validate these patterns, confirming the model's effectiveness in fault diagnosis.

This study proposes a fault diagnosis method based on digital twins. Experimental and simulation results demonstrate that the established digital twin model can accurately simulate the external characteristics of the actual physical circuit, validating its effectiveness in inverter fault diagnosis. This approach offers practical value for condition monitoring in actual urban rail train systems.

The study innovatively starts from a mathematical model and simulates the actual physical model through a virtual model, requiring only external characteristics to achieve system fault diagnosis, thereby enhancing diagnostic efficiency.

This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring. The purpose is to develop a reliable temperature compensation method for the system, improve the accuracy of slope stability monitoring and provide support for improving the safety and safety monitoring of engineering spoil slope and other projects.

Combined with theoretical analysis and experimental verification, the temperature compensation method is explored. The working principle of the hydrostatic leveling monitoring system is analyzed and the data processing formula, the temperature error calculation formula and the calculation formula for eliminating the error settlement value are derived. The temperature compensation method is established and verified by the field test of the engineering spoil slope which is disturbed by a debris flow.

The experimental results show that this method can reduce the error of the static level monitoring system by about 40 %. The field test shows that the fluctuation of slope settlement monitoring value is reduced after temperature compensation and the monitoring value is consistent with the actual situation, which has certain practicability.

The originality of this study is to derive a theoretical formula for quantifying/eliminating temperature errors in static leveling and to establish a practical temperature compensation method. The accuracy of the system is improved, which provides a reference for slope stability monitoring under complex environment (especially railway geotechnical engineering) and promotes the development of precision monitoring technology.