China Railway Research Articles

Study on the Effect of Root Density on the Shear Strength of Root-Soil Composite: A Case Study of Cynodon Dactylon

Since the Belt and Road Initiative was proposed, many slopes with poor stability have been formed in China's highway and railway infrastructure construction. In response to the national goals set during the 14th Five-Year Plan to strengthen the ecological security barrier and protect biodiversity, and in line with the philosophy that "lucid waters and lush mountains are invaluable assets," ecological protection technology has been widely applied in slope protection. However, current research and design have not considered the role of roots in retaining walls. This study uses an eco-friendly reinforced soil retaining wall project as an example to investigate the relationship between root density and the cohesion and internal friction angle of root-soil composites through direct shear tests. The results show that increasing root density significantly improves the cohesion and internal friction angle of root-soil composites. When the root density is 5%, the cohesion and internal friction angle increased by 40.57% and 51.41%, respectively, compared to the unreinforced soil sample, providing a theoretical reference for engineering design.

Regional subsidence monitoring and prediction along high-speed railways based on PS-InSAR and LSTM

The rapid construction of high-speed railways in China has forced more and more routes to pass through slow subsidence zones caused by groundwater extraction or underground mining. It is crucial to carry out deformation monitoring and prediction those areas along high-speed railways to ensure the safe operation. Twenty-nine periods of Sentinel-1A data between Taiyuan South Station and Taigu East Station were first processed using the PS-InSAR technique, and the ground subsidence sequences at ten typical points were selected. Then the Variational modal decomposition (VMD) was combined with the Adaptive Boosting Algorithm (AdaBoost), and the VMD-LSTMAda-LSTMAda model was constructed by combining the long short-term memory (LSTM) model for the prediction of regional ground subsidence along the high-speed railway. The results show that the cumulative subsidence within the 200 m buffer of the line centreline is − 37.58 − 89.19 mm, and the annual average subsidence rate is − 26.57 − 82.63 mm/y. The proposed model can reduce the complexity of the deformation sequence and combines with AdaBoost to improve the prediction accuracy of the LSTM model. It performs well in terms of RMSE, MAE, MAPE, and R2 at the two feature points (3703: RMSE = 0.82 mm, MAE = 0.25 mm, MAPE = 6.31%, and R2 = 0.94; 522: RMSE = 1.32 mm, MAE = 0.46 mm, MAPE = 4.92%, R2 = 0.95). The model improves the accuracy of regional subsidence prediction along the high-speed railway.

Impact of typical environments in China's western mountainous areas on the durability of railway concrete: a review

PurposeThis study aims to analyze the impact mechanism of typical environments in China's western mountainous areas on the durability of railway concrete and propose measures to improve durability.Design/methodology/approachWith the continuous promotion of infrastructure construction, the focus of China's railway construction has gradually shifted to the western region. The four typical environments of large temperature differences, strong winds and dryness, high cold and low air pressure unique to the western mountainous areas of China have adverse effects on the durability of typical railway structure concrete (bridges, ballastless tracks and tunnels). This study identified the characteristics of four typical environments in the western mountainous areas of China through on-site research. The impact mechanism of the four typical environments on the durability of concrete in different structural parts of railways has been explored through theoretical analysis and experimental research; Finally, a strategy for improving the durability of railway concrete suitable for the western mountainous areas of China was proposed.FindingsThe daily temperature difference in the western mountainous areas of China is more than twice that of the plain region, which will lead to significant temperature deformation and stress in the multi-layered structure of railway ballastless tracks. It will result in cracking. The wind speed in the western plateau region is about 2.5 to 3 times that of the plain region, and the average annual rainfall is only 1/5 of that in the plain region. The drying effect on the surface of casting concrete will significantly accelerate its cracking process, leading to serious durability problems. The environmental temperature in the western mountainous areas of China is generally low, and there are more freeze-thaw cycles, which will increase the risk of freeze-thaw damage to railway concrete. The environmental air pressure in the western plateau region is only 60% of that in the plain region. The moisture inside the concrete is more likely to diffuse into the surrounding environment under the pressure difference, resulting in greater water loss and shrinkage deformation of the concrete in the plateau region. The above four issues will collectively lead to the rapid deterioration of concrete durability in the western plateau region. The corresponding durability improvement suggestions from theoretical research, new technology development and standard system was proposed in this paper.Originality/valueThe research can provide the mechanism of durability degradation of railway concrete in the western mountainous areas of China and corresponding improvement strategies.

The Impact of Transportation Infrastructure on Manufacturing Energy Intensity: Micro Evidence from High-Speed Railway in China

This paper examines the potential of infrastructure improvements, particularly the operation of High-speed railway (HSR), to enhance the energy efficiency of firms. By regarding the operation of the China’s HSR as an exogenous shock, this paper relies on a difference-in-differences estimation to isolate the causal effect of the infrastructure improvement on manufacturing firms’ energy intensity. This paper finds that the operation of HSR has improved the manufacturing firms’ energy intensity through the catalyzing the proliferation of advanced management techniques, and this effect gradually decreases with the increase in distance between the firm and the HSR station. Moreover, HSR indirectly decreases energy intensity by fostering technological innovation, decreasing debt financing costs, and extending debt financing magnitude. The study also uncovers heterogeneous effects of HSR connectivity on manufacturing firms’ energy intensity, which are more pronounced in smaller cities and industries characterized by high concentration and low agglomeration. Furthermore, the impact of HSR connectivity on reducing energy intensity is more substantial in state-owned and larger firms compared to non-state-owned and smaller firms. JEL Classification: Q43, O13, R41, L60

International Transportation Infrastructure and China Enterprises Green Innovation: Evidence from the China Railway Express

The China Railway Express (CRExpress) is a vital international transportation infrastructure for the advancement of the Belt and Road Initiative and the expansion of international commerce, providing a significant opportunity for Chinese companies to undergo a sustainable transformation. We use a multi-period differences-in-differences model to investigate the relationship and mechanism between the opening of the CRExpress and green innovation of enterprises, based on the panel data of Chinese A-shared listed companies from 2007 to 2020. The results show that the opening of the CRExpress can significantly increase the logarithmic number of green patent applications by at least 5% in enterprises with a spoke radius of 250–450 km, and it also has a significant positive effect on different types of green patents to varying degrees. By examining the sub-items of ESG ratings, the opening of the CRExpress can promote the green innovation of enterprises through the improvement of E-score. Additionally, three pivotal mechanism pathways have been identified: the promotion of regional economic development, the alleviation of corporate financing constraints, and the reduction of corporate logistics expenses. Furthermore, we find that the effect of the CRExpress turns out larger on the green innovation of enterprises in the Secondary Industry and the Tertiary Industry, manufacturing industry, state-owned enterprises, and firms located in the eastern and central regions. Based on the empirical study, we provide policy implications for deepening the correlation between the CRExpress and green innovation.

Sustainable Development of the China Railway Express under the Belt and Road Initiative: Focusing on Infrastructure Reliability and Trade Facilitation

The China Railway Express (CR Express) is an important component of the Belt and Road Initiative (BRI). The sustainable development of CR Express provides critical support for regional economic integration and promotes a balanced development of the supply chain. Infrastructure reliability and trade facilitation greatly impact the operation of CR Express and are crucial for improving the competitiveness of transnational trade and cross-border efficiency. Inconsistent transportation infrastructure standards and low-efficient transportation service procedures affect the cross-border movement of cargo among countries. This paper integrates quantified metrics of infrastructure reliability and trade facilitation into a spatial friction model based on the electrical resistance theory, estimating the impact of these factors on the transportation flow of CR Express. Additionally, three scenarios of infrastructure reliability and trade facilitation are established for the four trade routes from Zhengzhou to Hamburg. Numerical experiments show that compared with inland river routes and traditional ocean routes, infrastructure reliability and trade facilitation significantly influence the transport flow of CR Express. These research results can provide a reference for the improvements of CR Express transportation efficiency and the simplification of customs clearance processes, potentially promoting the sustainable development of the CR Express supply chain to some extent.

Does transportation infrastructure contribute to urban entrepreneurship? Evidence from the high-speed railway in China

High-speed railways have a profound impact on entrepreneurship. Adopted China's city panel data, we use a time-varying DID model to estimate the influence of the high-speed railways on urban entrepreneurship and study its mechanism. The analysis results reveal that high-speed railways have improved the entrepreneurial vitality of cities. The mechanism test suggests that high-speed railway promotes entrepreneurship activities by accelerating human capital flow, strengthening producer services agglomeration, and promoting market integration. A range of robustness tests including a parallel trend test, placebo test, and PSM-DID model are used to ensure the reliability of the empirical results. Heterogeneity analysis and spatial analysis are used to deepen the research. Heterogeneity analysis reveals that high-speed railway construction is likely to motivate entrepreneurship in eastern cities, big cities, and cities with high-level business environments. The spatial analysis results show that the opening of the high-speed railways promotes the entrepreneurial level of surrounding cities. The research results help to evaluate the economic benefits of high-speed railway network expansion, and provide decision-making references for stimulating urban entrepreneurship.

Research on the Calculation Method and Influence Law of High-speed Railway Line Sound Source Propagation Attenuation Caused by Building Sheltering

Abstract In recent years, China’s rail transit system, particularly the high-speed railway network, has experienced rapid development. However, the issue of noise pollution along these railways has become increasingly severe. The accurate prediction of sound levels at specific points near buildings is challenging due to complex factors such as differences in line height, distance, and angle relative to the building. To address this challenge and improve predictions of sound propagation attenuation caused by building shelter from high-speed railway line sources, this study derives an integral expression for diffraction attenuation based on Curze and Meakawa’s point source acoustic diffraction theory. Numerical calculations are conducted to investigate the sound propagation attenuation patterns under different position relationships between buildings and railway lines. Field tests are also carried out along a high-speed railway in China. The findings are as follows: (1) The calculated results show a difference of less than 0.5 dB compared to measured values, indicating that they accurately reflect sound attenuation caused by building shelter. (2) The angle between the building and the railway as well as the distance between the sound point and the edge of the building significantly influence building shelter attenuation; with angle being most prominent among them within a frequency band of 500~2000 Hz resulting in an attenuation range of 0.6~15 dB variation should be considered when predicting noise levels at sensitive points or designing vibration and noise reduction measures accordingly. (3) Different distances between buildings and railway lines result in additional effects on attenuations.

A time-space network-based model for transportation service optimization of China Railway Express

This paper describes the development and optimization plans for the China Railway Express (CR Express). As a new type of international land transport organization, CR Express has emerged with the continuous expansion of China toward European investment and trade, and in particular, has expanded with the continuous progress of the One Belt and One Road (OBOR) initiative. In addition to improving the service quality of CR Express, the operating costs must be reduced for developing “smart railways” that serve “smart cities”. We propose a dual-objective-based function mathematical optimization model; the satisfaction of the cargo owner is considered, and the timeliness, transportation capacity, and goods category constraints of CR Express transportation are designed. Moreover, we present the normalized equivalent method of the two-objective function of the model. Finally, a case study is conducted against the background of certain trains in the western corridor of CR Express to validate the effectiveness of the model and research methods proposed in this study.

Exploring the dynamic impact of the Northern Sea Route on China-Europe multimodal transportation competition in the context of the Belt and Road Initiative

As Arctic sea ice continues to melt, the Northern Sea Route (NSR) is anticipated to become the third major China-Europe transportation corridor, alongside the Suez Canal Route (SCR) and China Railway Express (CRE). This study investigates the integration of the NSR into the Belt and Road multimodal transportation network and analyzes its dynamic competition with traditional corridors across heterogeneous regions and markets in China. To achieve this, we developed a novel hybrid multi-criteria decision-making (MCDM) framework to evaluate the NSR's potential as an alternative China-Europe trade route. This framework introduces a new criteria utility function (CUF) and integrates the Bayesian best-worst method (BBWM) and measurement of alternatives and ranking according to compromise solution (MARCOS) method. This approach evaluates and prioritizes routes based on cost, time, reliability, safety, sustainability, and convenience, thereby detailing the NSR's market advantages and business prospects. The findings suggest that simply increasing the frequency of transportation services is insufficient to attract Chinese customers to the NSR. Instead, the route's competitiveness is primarily determined by transportation costs. In future scenarios, the NSR will offer additional route options for China-Europe containerized intermodal transport, potentially serving as a complementary corridor to the SCR and CRE under certain conditions. Coastal and sub-coastal regions north of Fujian Province are potential markets for the NSR, while inland regions far from seaports are better suited for connections via the CRE. Notably, time-insensitive containerized cargoes, such as industrial accessories, mechanical equipment, and metal crafts, exhibit higher potential demand for the NSR. In contrast, time-sensitive commodities like fashion apparel, electronics, and medical devices are more likely to be transported by cross-border railroads due to their urgency. Stakeholders, including government agencies, shipping companies, and exporters, can utilize these insights to optimize China-Europe transport organization and effectively commercialize the NSR.

Experimental investigation and fluid-structure interaction modelling of the casting of self-compacting concrete for CRTS III slab track in the curved segments

Ensuring the casting quality of self-compacting concrete (SCC) is crucial for the operational safety and durability of China railway track system (CRTS) III slab track. However, the mechanisms of key factors influencing flow behaviors of SCC and structural responses remain insufficiently understood, nor is the relationship between flow behaviors and structural responses during casting. In this study, fluid-structure interaction (FSI) models of SCC casting were developed and verified by full-scale physical tests, comprising slump flow, L-box flow and casting of SCC in an actual track at the field of Laixi-Rongcheng high-speed railway. Through in-depth analysis on the casting process of SCC in curved segments with a super elevation of 80 mm, the relationship between flow behaviors and structural responses was established. Furthermore, the influence mechanisms of key factors on flow behaviors and structural responses were investigated systematically. Results show that during gravity-fed SCC casting, its flow velocity diminishes, thus increasing the static pressure and the forces exerted on the slab by SCC. These vertical and lateral forces increase to 147.16 and 7.83 kN through three stages of development, acceleration and stabilization, resulting in commensurate structural responses. At the end of casting process, the central region of the slab exhibits maximum vertical deformation of 0.95 mm and tensile stress of 1.07 MPa. The tension rods at the side with lower elevation bear greater vertical and lateral forces than the ones at the side with higher elevation. The rise of funnel height from 1.05 to 1.35 m accelerates the casting process but increases the forces exerted by SCC by up to 26 % and augments the associated response of entire structures, whereas the funnel diameter shows little effect. Increasing yield stress of SCC from 9.3 to 49.3 Pa produces a more uniform flow morphology and thus higher static pressure and force by SCC in the middle region of the slab, impacting the structural responses by up to 15 %. The growth of plastic viscosity from 59 to 99 Pa⋅s significantly affects the volume rate and casting time by up to 66 % but has little effect on the flow morphology, fluid pressure and structural responses. In order to ensure high quality casting of SCC, five clamping beams are suggested with two beams positioned at either side of the slab and the other three evenly placed along the middle region of the slab.

Support Vector Machine-Based Fault Diagnosis under Data Imbalance with Application to High-Speed Train Electric Traction Systems

The safety and reliability of high-speed train electric traction systems are crucial. However, the operating environment for China Railway High-speed (CRH) trains is challenging, with severe working conditions. Dataset imbalance further complicates fault diagnosis. Therefore, conducting fault diagnosis for high-speed train electric traction systems under data imbalance is not only theoretically important but also crucial for ensuring vehicle safety. Firstly, when addressing the data imbalance issue, the fault diagnosis mechanism based on support vector machines tends to prioritize the majority class when constructing the classification hyperplane. This frequently leads to a reduction in the recognition rate of minority-class samples. To tackle this problem, a self-tuning support vector machine is proposed in this paper by setting distinct penalty factors for each class based on sample information. This approach aims to ensure equal misclassification costs for both classes and achieve the objective of suppressing the deviation of the classification hyperplane. Finally, simulation experiments are conducted on the Traction Drive Control System-Fault Injection Benchmark (TDCS-FIB) platform using three different imbalance ratios to address the data imbalance issue. The experimental results demonstrate consistent misclassification costs for both the minority- and majority-class samples. Additionally, the proposed self-tuning support vector machine effectively mitigates hyperplane deviation, further confirming the effectiveness of this fault diagnosis mechanism for high-speed train electric traction systems.

Research on Competitive Strategy of Electric Company—Taking China Railway High-speed Railway Electric Equipment Co.

Research on Competitive Strategy of Electric Company—Taking China Railway High-speed Railway Electric Equipment Co.

Integrated optimization of train stop planning and seat allocation for high-speed railways based on active management for dynamic demand

ABSTRACT Proactive demand management methods can achieve a trade-off between supply and demand for high-speed railways. Focusing on multi-type demand configurations, four active demand management methods were designed, two single-scenario and two multi-scenario methods. An optimization model of stop planning and seat allocation was constructed to minimize the difference between demand and supply, number of trains, and train-stop costs. The number of train stops, transport capacity, and train occupancy rates were considered. Particle swarm optimization and CPLEX were combined to handle this significant linear programming problem. A real case study of different demand scenarios based on the Hohhot-Beijing high-speed railway in China verified the feasibility of active demand management methods. The results indicate that integrated optimization can be justified with mixed load patterns. Compared with the original scheme, the optimized scheme reduced the number of trains by 23.4% and increased train occupancy rate by more than 36.7%.

Research on the path of effective management of participation in joint-venture railway companies by China railway group

Research on the path of effective management of participation in joint-venture railway companies by China railway group

PC-Kriging-powered parallelizing Bayesian updating for stochastic vehicle-track dynamical system with contact force measurements and Gaussian process discrepancy model

High-precision vehicle-track coupled dynamical models play a vital role in assessing the running safety of the vehicle, tracking fatigue behavior, and establishing a digital twin for high-speed railways. This study established a high-fidelity vehicle-track coupled dynamical model as a forward solver, which was then updated in a Bayesian inference framework based on the field tests of rail irregularities and wheel/rail normal contact forces. The prediction errors corresponding to different time steps were represented through a Gaussian process (GP) model characterized by a covariance function with the Gaussian kernel to incorporate the correlation between different time steps. To cope with the considerable expense of the likelihood function calculations with large-scale loop operations and the computational burden due to the large batch of repetitive evaluations of the high-fidelity forward model involved in the stochastic sampling from the posterior probability distribution, a metamodel-powered parallelizing stochastic sampling scheme was adopted. The posterior distribution could be formulated by replacing the expensive explicit model evaluation involved in the likelihood function with a Polynomial-Chaos-Kriging (PC-Kriging) predictor providing a surrogate mapping between the wheel/rail normal contact forces and physical parameters. Finally, a parallelizing computing scheme running across multiple CPU cores on high-performance computers was realized to sample from the vectorized formula of the emulator-powered posterior distribution. Field test data from a high-speed railway in China was adopted to demonstrate that the Bayesian inference scheme can quantify the uncertainties of the core physical parameters of the high-fidelity vehicle-track coupled dynamical system by efficiently trading off accuracy and computational efficiency.

Assessing the impact of China Railway Express operations on the development of Chinese cities: China-Europe freight routes evolution and city development analysis

The operation of the China Railway Express (CRE) has diversified freight transportation between China and Europe, expanding the international freight channels in Chinese cities where CRE operates. However, the relationship between the evolution of China-Europe freight routes and the development of Chinese cities remains unclear. Therefore, we propose a potential model to assess the evolution of CRE routes and develop an indicator system to measure city sustainability. We employ a coupled coordination degree model (CCDM) and structural equation modeling (SEM) to determine the impact of CRE on the development of these cities. Findings reveal several key insights. Firstly, CRE has facilitated the expansion of China-Europe freight routes in Chinese cities, significantly enhancing the accessibility of China-Europe integrated inland transportation. Secondly, the growth of freight routes between China and Europe has exerted a substantial influence on the long-term development of Chinese cities, particularly inland cities. The positive relationship between route evolution and city development has strengthened over time. Lastly, the expansion of China-Europe freight routes indirectly contributes to the development of inland cities, primarily through stimulating innovation, industry scale, financial growth, and international trade. In contrast, coastal cities mainly benefit from the direct promotion of the international trade levels.

Communication security analysis of fully electronic interlocking systems

Communication security in fully electronic interlocking systems is one of the key factors ensuring the safe and reliable operation of the entire system. EN50159 is an important standard in the European railway communication sector, aimed at ensuring the safety, reliability, and efficiency of railway transportation. According to the communication security standards of EN50159, there are six types of security risks in closed communication: data duplication, deletion, insertion, misordering, delay, and corruption. This paper analyzes and explains the aspects of communication security that need to be considered based on the safety communication standards of China's railway signaling system and the signal safety standards in EN50159, focusing primarily on communication security and reliability.

Mechanical characteristics of track slab and clamps during the pouring of self-compacting concrete in the China Railway Track System III slab track

The pouring of self-compacting concrete (SCC) is crucial for ensuring the construction quality and comfort of slab tracks. In this study, a fluid–structure coupling pouring model of SCC was established based on the coupled Eulerian–Lagrangian (CEL) approach. It was applied to trace the forces and displacements of track slab and clamps during SCC pouring. The influences of some key parameters, such as the pouring equipment, technology, and rheological properties, were investigated, including the height and diameter of the funnel, pouring velocity, and plastic viscosity of the SCC. The results indicated that during pouring, the floating force and maximum vertical displacement of the track slab, as well as the vertical forces of the clamps, initially remained stable before undergoing rapid changes, eventually reaching stable values. The flow velocity of SCC in the pouring hole and its rebound primarily influenced these mechanical indicators. The funnel height positively affected the floating force of the track slab, negatively affected the vertical forces of the clamps, and slightly affected the peak values of the maximum vertical displacement of the track slab. By contrast, the funnel diameter had little influence on these mechanical behaviour indicators. As the pouring velocity increased, the floating force of the track slab and vertical forces of the clamps significantly increased. Moreover, the peak values of the maximum vertical displacement of the track slab increased to 0.47 mm at a pouring velocity of 0.03 m/s. In the case of low plastic viscosity, an increase in plastic viscosity led to a visible decline in the floating and clamp forces. However, when the plastic viscosity exceeded 80 Pa•s, further changes had little effect on the mechanical indicators owing to the combined effects of excessively low flow velocity and rebounding.

Construction of Hub Location Model Based on Genetic Algorithm

This paper conducts an analysis of the cost composition of the China Railway Express train operation system, taking into account the choice of exit ports and the time value cost of goods during the operation of trains by China Railway Express. A site selection optimization model is then established with the objective of minimizing the total cost of the China Railway Express service network. A genetic algorithm is designed to solve the optimization model. The location model is then addressed using the designed algorithm, leading to the determination of the site selection plan for the central hub. The optimization results of the site selection plan are subsequently verified under different conditions. The node cities of the China Railway Express in China and the source cities of the freight trains are used as the objects of analysis during the process of solving the location model. The findings indicate that selecting Xi’an as the central hub and Chengdu as the sub-hub could result in an 18.1% reduction in the system cost of China Railway Express, while maintaining the advantage of logistics costs, particularly in scenarios where the freight subsidy is canceled. Furthermore, this choice ensures the stability of the logistics cost of the entire system, even in the event of serious congestion.