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 study aims to investigate the fatigue behavior and failure modes of bolted lap joints using Modified Tensile Specimens (MTS) under various cyclic load conditions. Emphasis is placed on identifying the relationship between load amplitude, fatigue life, and damage progression in low-carbon steel assemblies.

An experimental approach was adopted using MTS specimens fabricated from St 12 03 cold-rolled steel, joined with Grade 8.8 M4 bolts. Cyclic fatigue tests were conducted under zero-based loading at seven distinct force levels. Fracture surfaces were visually analyzed to identify dominant failure mechanisms.

The results revealed a strong inverse correlation between applied cyclic load and fatigue life. Three distinct failure modes were identified: bolt shear at high loads (5.4 kN), interface cracking and slippage at moderate loads (4.9-5.1 kN), and plate tearing or stable fatigue behavior at lower loads (=4.1 kN). The results highlight a progressive transition in failure mechanisms, from bolt shear at high loads to plate tearing and interface cracking at lower loads, providing essential insights for fatigue-resistant bolted joint design.

This study offers original insights into the fatigue behavior of bolted lap joints using MTS, a relatively underexplored configuration in fatigue assessment. By experimentally evaluating failure modes under varied cyclic load levels, the authors uncover critical transitions in damage mechanisms—from bolt shear to interface cracking and plate tearing—depending on the applied load. Unlike many existing studies focused on numerical modeling or bonded joints alone, this work provides empirical data rooted in real-world fastening conditions using cold-rolled low-carbon steel.

Adding an appropriate pre-sag to the geometry of simple catenary systems for electric railways can improve their performance in dynamic interaction with the pantographs of trains operating under them. The value of pre-sag can be obtained by empirical approximation or computationally expensive optimisation. This study aims to define a simple but accurate method to determine a suitable pre-sag without dynamic simulations and to find its limitations.

A quasi-static method to determine the ideal value of pre-sag is described based on elasticity variations. It considers variations of the static contact force. The limits of this method are investigated by comparing it to a parametric dynamic simulation study. In the dynamic simulation, an optimal level of pre-sag is identified for each contact force level. The influence of the speed in the dynamic simulation results is expressed in two parameters: the quasi-static influence in the mean contact force and the dynamic influence in the ratio between the vehicle speed and the wave propagation speed in the contact wire.

The comparison between the suggested method and the dynamic simulations shows a high consistency up to a speed limit of around 40 % of the wave propagation speed. The best agreement with the dynamic results is achieved by calculating the optimal pre-sag based on the absolute elasticity variation.

The simplified approach for determining the pre-sag is valid for low-speed applications, such as suburban railway lines. For these cases, a highly suitable geometry can be obtained with the suggested method, meaning a significantly reduced computational effort. As a case study for this work, the results are applied to a Swedish suburban rail line upgrade case.

The static uplift force is added as a varied parameter in dynamic simulations. The shift in system behaviour from low to high dynamics is described, and how the benefits from pre-sag are visible and then disappear. The limit value of the low-dynamics regime is identified to be 40 %.

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.

As a key structure in the railway power supply system, the overhead catenary pillar carries the entire weight and dynamic load of the contact suspension device and supporting equipment. Its stability and reliability are directly related to the operational safety and efficiency of electrified railways.

Regarding the phenomenon of abnormal shedding of coating above the support under the cantilever of the catenary pillar in the track running line, a three-dimensional model is established to analyse the rigid cantilever type catenary and the force analysis of the cantilever part is carried out by using ABAQUS to calculate the contact force of the bow network under different running speeds of the high-speed train. The load is applied at the locator end of the simplified model of the cantilever to get the support reaction force at the connection between the cantilever and the support.

The support reaction force is applied as a load to the three-dimensional model of the pillar support; the stress cloud and the stress extreme value of 86.14 MPa are obtained for the pillar and the support part and the fatigue life of the pillar's key parts is calculated to be 12.02 years, respectively.

The upper part of the lower support of the high-speed rail catenary pillar is subjected to the alternating load transmitted by the bow net, which causes the fretting damage at this position, resulting in the abnormal peeling of the coating on the upper part of the lower support. Through combining the ABAQUS analysis with the structural characteristics and operating conditions of the catenary system, the main causes of component failure are determined.

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.

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.

Conventional high-speed railways (HSR) subgrade design methods remain constrained by platform-dependent drafting systems, leading to data interaction hindrances and redundant design processes. This study strives to develop a digital earthwork design methodology that enhances design while reducing collaborative expenses.

A novel digital subgrade design approach, utilizing sophisticated analysis and modeling tools customized for different subgrade elements, is put forward in this study. The methodology incorporates the following essential steps: (1) the advancement of digital analysis and modeling techniques for diverse subgrade components, including surfaces, filling, slopes, retaining structures, and foundation treatments; (2) the formulation of a digital design principle repository incorporating various slope protection combinations; (3) the establishment of a comprehensive digital design framework and process for subgrade cross-sections; and (4) the development and implementation of an open-source digital design system.

The proposed method liberates subgrade design from the constraints of conventional drawing platforms, elevating efficiency, intelligence, and flexibility. The open software architecture and code have achieved over 60% efficiency gains in design workflows during its deployment on three major high-speed rail projects: the Baotou-Yinchuan HSR corridor, Shenyang-Baihe HSR network, and Weifang-Yantai HSR system.

This paper introduces an innovative digital design methodology that enables modular and parametric design for railway subgrade sections. The proposed approach provides a digital base for the intelligent design and maintenance of the next-generation high-speed railway.

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.

With the rapid advancement of China's high-speed rail network, the density of train operations is on the rise. To address the challenge of shortening train tracking intervals while enhancing transportation efficiency, the multi-objective dynamic optimization of the train operation process has emerged as a critical issue.

Train dynamic model is established by analyzing the force of the train in the process of tracing operation. The train tracing operation model is established according to the dynamic mechanical model of the train tracking process, and the dynamic optimization analysis is carried out with comfort, energy saving and punctuality as optimization objectives. To achieve multi-objective dynamic optimization, a novel train tracking operation calculation method is proposed, utilizing the improved grey wolf optimization algorithm (MOGWO). The proposed method is simulated and verified based on the train characteristics and line data of CR400AF electric multiple units.

The simulation results prove that the optimized MOGWO algorithm can be computed quickly during train tracks, the optimum results can be given within 5s and the algorithm can converge effectively in different optimization target directions. The optimized speed profile of the MOGWO algorithm is smoother and more stable and meets the target requirements of energy saving, punctuality and comfort while maximally respecting the speed limit profile.

The MOGWO train tracking interval optimization method enhances the tracking process while ensuring a safe tracking interval. This approach enables the trailing train to operate more comfortably, energy-efficiently and punctually, aligning with passenger needs and industry trends. The method offers valuable insights for optimizing the high-speed train tracking process.