This study aims to propose a novel identification method to accurately estimate linear and nonlinear dynamics in permanent magnet synchronous linear motor (PMSLM) based on the time-domain analysis of relay feedback.

A mathematical model of the PMSLM-based servo-mechanical system was first established, incorporating the aforementioned nonlinearities. The model's velocity response was derived by analyzing its behavior as a first-order system under arbitrary input. To induce oscillatory dynamics, an ideal relay with artificially introduced dead-time components was then integrated into the servo-mechanism. Depending on the oscillations and the time-domain analysis, nonlinear formulas were deduced according to the velocity response of the servo-mechanism. Afterwards, the unknown model parameters can be solved on account of the cost function which utilizes the discrepancy between nominal position characteristics and temporary position characteristics, both of which are extracted from the oscillations. The proposed recognition method was validated through a two-stage process: (1) numerical simulation and calculation, followed by (2) real-time experimental verification on a direct-drive servo platform. Subsequently, leveraging the identification results, a novel control strategy was developed and its tracking performance was benchmarked against conventional control schemes.

Simulation results demonstrate that the proposed method achieves estimation accuracy within 8%. Building on this, a novel control strategy is developed by incorporating both friction pulsation and force pulsation identification results into the feedforward compensator. Comparative experiments reveal that this strategy significantly enhances tracking and positioning performance over traditional control schemes. In a word, this new identification method can be used in different process control and servo control systems. Moreover, parameter auto-tuning, feed forward compensation or disturbance observer can be investigated based on the obtained information to improve the system stability and control accuracy.

It is of great significance for the performance improvement of rail transit motor control equipment, such as electro-mechanical braking systems. By enhancing the efficiency of motor control, the performance of the product will be more outstanding.

This paper aims to analyze the transverse vibration characteristics of the high speed train window glass when passing through tunnel.

The lateral vibration acceleration response of glass chamber of high-speed train CR400BF-A on Beijing - Chengdu high-speed railway was tested at different speeds through the tunnel entrance, exit, tunnel interior, Tunnel Group and rendezvous time in the tunnel, the lateral distribution characteristics of vibration frequency and vibration power amplification coefficient of glass of high-speed train were analyzed.

The results show that: The vibration of the high-speed train glass increases significantly during the tunnel, and the amplitude of vibration acceleration in the tunnel is significantly higher than outside the tunnel as the travel speed increases; the amplitude of lateral vibration acceleration of the glass of a high-speed train does not vary with changes in tunnel length and is not affected by the aerodynamic effects of the tunnel when traveling inside the tunnel, but its vibrations create noticeable fluctuations during variations when encountering oncoming traffic; The vibration characteristics of the high-speed train glass are forced harmonic vibrations, the excitation frequency does not vary with travel speed and travel position changes inside and outside the tunnel. The lateral vibration acceleration of the glass of a high-speed train is applied vertically and uniformly to the glass surface as an "inertial force" and creates a cyclic bending vibration stress that can easily lead to fatigue damage.

The research results provide guidance for the prevention of glass failure in high-speed trains.

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 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 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 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.

The indoor vibration compaction test (IVCT) was a key step in controlling the compaction quality for high-speed railway graded aggregate (HRGA), which currently had a research gap on the assessment indicators and compaction parameters.

To address these issues, a novel multi-indicator IVCT method was proposed, including physical indicator dry density (ρ_d) and mechanical indicators dynamic stiffness (K_rb) and bearing capacity coefficient (K₂₀). Then, a series of IVCTs on HRGA under different compaction parameters were conducted with an improved vibration compactor, which could monitor the physical-mechanical indicators in real-time. Finally, the optimal vibration compaction parameters, including the moisture content (ω), the diameter-to-maximum particle size ratio (R_d), the thickness-to-maximum particle size ratio (R_h), the vibration frequency (f), the vibration mass (M_c) and the eccentric distance (r_e), were determined based on the evolution characteristics for the physical-mechanical indicators during compaction.

All results indicated that the ρ_d gradually increased and then stabilized, and the K_rb initially increased and then decreased. Moreover, the inflection time of the K_rb was present as the optimal compaction time (T_lp) during compaction. Additionally, optimal compaction was achieved when ω was the water-holding content after mud pumping, R_d was 3.4, R_h was 3.5, f was the resonance frequency, and the ratio between the excitation force and the M_c was 1.8.

The findings of this paper were significant for the quality control of HRGA compaction.

Weathering steel has excellent resistance to atmospheric corrosion, but still faces complex environmental corrosion problems during long-term operation. This paper mainly studies the corrosion problem of weather resistant steel materials for railway freight car bodies with a load capacity of 70 tons.

The paper analyzes the corrosion characteristics of weather resistant steel materials for truck bodies through macroscopic and microscopic methods including metallographic microscopy, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Electrochemical analysis shows that the rust layer on the surface of weathering steel changes the surface state of the material, and also proves that weathering steel used in trucks undergoes electrochemical corrosion under atmospheric corrosion. At the same time, ion chromatography technology is used to study the corrosive ions mainly present in the residual liquid and foam solution inside the vehicle body.

The corrosion of truck body materials is mainly electrochemical corrosion, and the corrosion of door materials is more obvious than that of other parts. The corrosion products are mainly Fe oxides and hydroxides. There are high concentrations of Cl^- and SO42^- ions in the residual liquid and foam solution at the bottom of the freight car, which are the main factors causing corrosion of the railway freight car body.

The foam adhesive around the door panel is in a moist state for a long time, and corrosive ions will accelerate the electrochemical corrosion of the weather resistant steel material of the door panel. Therefore, the corrosion of the cargo door panel is more severe than other components.

Over the last decade, African rail sectors have applied hybrid reform models to catch up with the subregion's lagging rail performance compared to other regions. With this in mind, this paper aims to study the effect of deregulation on rail transport demand. Following an abundant literature on deregulation in Europe and Asia, this study focuses on structural and regulatory reforms.

The investigation methodology is in line with the investigations of Mizutani (2019) and Smith, Benedetto, and Nash (2018). This paper uses a seemingly unrelated model (SURE) for general estimation and a random effect least square model for regional block estimation on a panel of 26 countries for 15 years between 2000 and 2015.

The main results show that structural reforms positively affect passenger transport demand, but negatively affect freight transport demand. The level of competition stimulates demand for freight transport. Privatization of operators positively affects freight transport demand, but has no significant effect on passenger transport demand. The introduction of a regulatory authority has a positive effect on demand for passenger transport, and in certain regional blocs, it affects demand for freight transport, with the existence of corridors shared between several countries.

This study is carried out in the sub-Saharan African sub-region. Indeed, the importance of the rail sector and the dilapidated state of many of its infrastructures should prompt a more abundant literature on the subject of the effectiveness of deregulation movements. We also evaluate the effect of vertical or horizontal separation and the introduction of an independent regulator in the rail sector on overall demand for transport service.

The rapid development of China's railway construction has led to an increase in data generated by the high-speed rail (HSR) catenary system. Traditional management methods struggle with challenges such as poor information sharing, disconnected business applications and insufficient intelligence throughout the lifecycle. This study aims to address these issues by applying building information modeling (BIM) technology to improve lifecycle management efficiency for HSR catenary systems.

Based on the lifecycle management needs of catenary engineering, incorporating the intelligent HSR "Model-Data Driven, Axis-Plane Coordination" philosophy, this paper constructs a BIM-based lifecycle management framework for HSR catenary engineering.

This study investigates the full-process lifecycle management of the catenary system across various stages of design, manufacture, construction and operation, exploring integrated BIM models and data transmission methods, along with key technologies for BIM model transmission, transformation and lightweighting.

This study establishes a lossless information circulation and transmission system for HSR catenary lifecycle management. Multi-stage applications are verified through the construction of the Chongqing-Kunming High-Speed Railway, comprehensive advancing the intelligent promotion and high-quality development of catenary engineering.