Development Of High-speed Railway Research Articles

Running Safety Assessment of a High-Speed Train on Bridges During Braking Under Near-Fault Ground Motions

This study aims to investigate the adverse effects of near-fault ground motions on the long-term development of high-speed railways. In this paper, the ground motions are analyzed based on the Train–Track–Bridge Coupling Braking System (TTBCBS) which has been validated during earthquakes. The effects of earthquakes on the whole system are discussed in depth, focusing on the random nature of earthquakes, the impulsive character of near-fault earthquakes and the effects of different initial speeds on the system behavior. The results show that under random earthquakes, the probability of train derailment gradually increases with the increase of peak ground acceleration (PGA) of earthquakes. When the PGA exceeds 0.2[Formula: see text]g, the train is highly susceptible to derailment and the bridge itself may incur damage. When analyzing the nature of pulses of near-fault ground motions, it was found that the responses induced by class B and class C pulses are significantly similar. Meanwhile, the calculated values of derailment coefficients are basically the same when the PGA of class A pulse wave is at 0[Formula: see text]g and 0.1[Formula: see text]g. This suggests that train braking somewhat mitigates the response induced by near-fault ground motions. Furthermore, the value of improved spectral intensity (SI) for the running safety during earthquakes indicates that the increase in seismic intensity is detrimental to the system. In terms of the effect of train initial speeds on the system during earthquakes, it is observed that the system response reaches the lowest point when the train speed is 250[Formula: see text]km/h, which is more favorable to the smooth deceleration of the train. When the train speed is 400[Formula: see text]km/h, the system response reaches its maximum value. These research findings provide crucial insights and guidance for seismic safety design and management of high-speed railways.

Optimization of ticket pricing for high-speed railway considering full competitive environment

The rapid development of high-speed railways (HSR) worldwide has provided a fast, convenient, safe, and comfortable mode of transportation. It is also an important public transportation tool for green travel, contributing to the reduction of carbon emissions. HSR has a strong competitive advantage in long-distance passenger transportation, but it faces significant competition from the aviation industry. Airlines attract passengers with discounted fares and differentiated pricing strategies, apart from shorter travel times. Therefore, it is necessary for railway enterprises to enhance their competitiveness through differentiated pricing methods for HSR. In this study, we focus on optimizing a long-distance origin-destination (OD) pair and creating a competitive market environment by considering all operating trains and flights for the selected OD pair. We aim to improve the realism of the study by considering passengers’ fully rational travel choice behavior. To reduce the complexity of variables, passengers are grouped based on their expected departure time and income level. A mixed integer linear programing model is developed to address the problem, aiming to minimize overall travel costs for passengers while ensuring that the income of the railway enterprise does not fall below a specified value. By setting this specific value, the maximum revenue of HSR train tickets can be obtained.

Review of laser cladding coating on wear and fatigue of railway wheels/rails

With the rapid development of high-speed railway, wheel/rail premature wear and fatigue cracks occur frequently. Laser cladding high-quality coatings with high wear resistance and fatigue resistance on the damaged surface of wheel/rail can prolong its service life. In this review, the latest research progress of laser cladding Fe-based, Co-based and Ni-based coatings on the wear and fatigue of railway wheels/rails at home and abroad is reviewed. It is concluded that the wear resistance and fatigue resistance of Co-based alloy coatings are better than those of other alloy coatings. Adding strengthening elements to alloy powders can improve the welding process and improve the comprehensive properties of the coatings. Additionally, the laser cladding of railway wheel/rail is further envisaged as well.

Damaging effects of earth fissures on high-speed railway bridges: Insights from physical experiments and numerical simulations

Earth fissure is a typical geological phenomenon related to surface rupture. With the rapid development of high-speed railways (HSRs) in recent years, earth fissure disasters pose a serious challenge to the construction and subsequent safe operation of HSRs. Here, we aimed to investigate the damaging effect of earth fissure activities on HSR bridges spanning the earth fissure zone. Taking the Shuixiu earth fissure of Da-Xi HSR as the prototype, a large-scale laboratory physical experiment with geometric model scale 1:20 was carried out to reveal the deformation and failure characteristics of HSR bridges under earth fissure activity. In addition, the damage influence range and damage mode of HSR bridges crossing earth fissures are further determined by numerical simulation. The results show that the earth fissure activity mainly has damaging effects on the structure of HSR bridges near the earth fissure zone, which is mainly manifested as uneven settlement of reinforced concrete pile, bending deformation of box girder and cracking of track slab. The width of the influence zone of Shuixiu earth fissure on the HSR bridge is determined to be 32.4 m. Moreover, the pile-end pressure on the hanging wall side of the earth fissure gradually decreases with the earth fissure activity, while that on the footwall side increases significantly. Most importantly, it is emphasized that a practical long-term monitoring and early warning system of HSR bridge structures should be established to prevent the hazards caused by earth fissure activities. The above understanding will benefit to the design, construction and operation of Da-Xi HSR line, and also provide significant guidance and reference to the construction of HSR bridges in other earth fissure prone areas.

Reflection on methodology of the correlation between electromagnetic interference and safety in high-speed railways

PurposeIn the continuous development of high-speed railways, ensuring the safety of the operation control system is crucial. Electromagnetic interference (EMI) faults in signaling equipment may cause transportation interruptions, delays and even threaten the safety of train operations. Exploring the impact of disturbances on signaling equipment and establishing evaluation methods for the correlation between EMI and safety is urgently needed.Design/methodology/approachThis paper elaborates on the necessity and significance of studying the impact of EMI as an unavoidable and widespread risk factor in the external environment of high-speed railway operations and continuous development. The current status of research methods and achievements from the perspectives of standard systems, reliability analysis and safety assessment are examined layer by layer. Additionally, it provides prospects for innovative ideas for exploring the quantitative correlation between EMI and signaling safety.FindingsDespite certain innovative achievements in both domestic and international standard systems and related research for ensuring and evaluating railway signaling safety, there’s a lack of quantitative and strategic research on the degradation of safety performance in signaling equipment due to EMI. A quantitative correlation between EMI and safety has yet to be established. On this basis, this paper proposes considerations for research methods pertaining to the correlation between EMI and safety.Originality/valueThis paper overviews a series of methods and outcomes derived from domestic and international studies regarding railway signaling safety, encompassing standard systems, reliability analysis and safety assessment. Recognizing the necessity for quantitatively describing and predicting the impact of EMI on high-speed railway signaling safety, an innovative approach using risk assessment techniques as a bridge to establish the correlation between EMI and signaling safety is proposed.

РАЗВИТИЕ ТЕОРЕТИЧЕСКИХ ОСНОВ УПРАВЛЕНИЯ РИСКАМИ КРУПНЫХ ИНФРАСТРУКТУРНЫХ ГЧП-ПРОЕКТОВ

The purpose of this article is to develop the theoretical foundations of risk management in the implementation of large infrastructure projects with government participation using the example of the development of high-speed railways in Russia. The relevance of this topic is due to the fact that for Russia, high-speed highways are a completely new type of transport infrastructure, the creation of which requires the development of existing views and approaches to risk management of large infrastructure projects with government participation. The impact of high-speed highway projects on a country’s economy is difficult to overestimate, as they affect many factors: from stimulating development to improving the quality of life of the population, which is why studying existing tools and proposing new views on risk management that increase the success of projects with government participation is one of the key issues to be addressed.

A CALCULATION METHOD FOR HIGH-SPEED RAILWAY CAPACITY BASED ON IMPROVED TRAIN DEDUCTION METHOD

A reasonable calculation of railway capacity is very important for research. With the rapid development of high-speed railways, more and more differences between traditional and modern railways have emerged in the transportation organization and capacity calculation methods. In this article, the calculation methods used under different conditions with different train types are studied based on the train deduction method. Train deduction is a method that calculates the number of trains that cannot pass through the line when other trains change their stop plan or operation speed based on the coefficient of deduction method, which is widely used in China. Then, optimized models for trains with the same-speed and different-speeds are built to determine the maximum number of trains. These models are built based on the constraints of passenger service quality and overtaking times. In addition, the models are solved based on a train operation plan. Hence, the capacity calculated by these methods is more reasonable for the actual condition. Finally, an actual case of Beijing–Shanghai high-speed railway is implemented and tested with the model. The optimal capacity scheme is simulated and analysed, and the result agreed well with the railway transport enterprise.

Spatiotemporal Heterogeneity of Carbon Dioxide Emissions: Evidence from High-Speed Railway Operations in China

Carbon dioxide (CO2) emissions reduction has become an ever-growing concern in China and the government has proposed the goals of carbon peak and carbon neutrality. To better address this concern, this work pays particular attention to high-speed railway (HSR) operations and examines their spatiotemporal effects and potential mechanism on CO2 emissions. Using a geographically and temporally weighted regression (GTWR) model to fit a balanced panel dataset from the period 2008 to 2018, we have the following main findings. First, the GTWR model performs better than the pooled panel regression model as it considers temporal and spatial variations in factors of CO2 emissions simultaneously. Second, the temporally varying coefficients of HSR operations indicate their consistent contributions to emissions reduction, suggesting that the national development of HSRs can provide significant emissions reduction benefits. Third, as revealed by the spatially varying coefficients of HSR operations, most provinces can mitigate CO2 emissions by promoting HSRs, particularly in Shanxi, Hebei, and Shaanxi, owing to the larger contributions of HSR operations to CO2 emissions reduction. Finally, the contributions of HSR operations to emissions reduction can be transmitted through the mechanism of technological progress. These findings can offer valuable insights into cross-collaborative and province-specific policymaking for mitigating CO2 emissions.

How does high-speed railway affect green technology innovation? A perspective of high-quality human capital

Green development is the main theme of modern development in China and even the world. Green development depends on green technology innovation (GTI). Therefore, for developing countries like China in the stage of economic transition, it is urgent to accelerate GTI to gain sustained advantages in the new round of international competition. As an important representative of contemporary rapid transportation, high-speed railway (HSR) can not only alleviate the rapidly growing transportation demand of the public, but also have potential benefits to the energy consumption structure and environmental quality. Whether and how HSR affects GTI has become the focus of this paper. Hence, by employing the panel data of 286 cities in China from 2007 to 2018 with the time-varying DID model, this paper verifies that HSR development can contribute to GTI. The main findings of this paper are as follows: (1) The operation of HSR can not only make the incremental development of GTI, but also improve the quality of GTI simultaneously. Moreover, the quality improvement effect of HSR is greater than the quantity increment effect. (2) Heterogeneity analysis shows that the positive effect of HSR on GTI is more significant for cities that have implemented LCCP. (3) This paper verifies the mediating effect of high-quality human capital. The opening of HSR further stimulates GTI by improving the level of high-quality human capital in cities and increasing the opportunities for knowledge exchange and diffusion. Based on the above findings, this paper proposes some policy recommendations to help developing countries achieve GTI with positive externalities.

Research on the impact of air-blowing on aerodynamic drag reduction and wake characteristics of a high-speed maglev train

The maglev train fills the speed gap between ground transportation and airplanes. However, the increasing train speed results in greater energy losses due to increased aerodynamic drag, impeding the green and sustainable development of high-speed railways. This study employs the numerical simulation method to explore the effects of installing air-blowing slots on the surface of the TR08 maglev train's tail car and blowing air along three different directions at two different speeds on drag reduction and the characteristics of the wake flow field. Among them, only blowing air along the streamwise direction at speeds of 12 m/s (X12) and 24 m/s (X24) shows drag reduction effects of 2.06% and 6.53%, respectively. However, considering the energy efficiency, only X12 achieves a net energy saving of 58.96%, while the energy consumption by blowing air and saving by reducing drag in X24 are roughly balanced. Air-blowing reduces the aerodynamic lift of the tail car (Cl), with blowing air along the perpendicular direction at 24 m/s (Z24) reducing the Cl by 99.57%. Additionally, Z24 reduces the maximum velocity value of the train-induced air flow (Usmax¯) by 61.91%. The research findings provide new insight and data support for the development of blowing/suction drag reduction techniques.

Can high-speed railway promote regional market integration? Evidence from China

The rapid development of high-speed railways is an important manifestation of transportation modernization in China, and has a huge influence on the integration of China's regional market. The predominance of passenger transport in China's high-speed rail (HSR) network makes it difficult to explain the influence of HSR on regional market integration issues in the previous research paradigm of economic geography based on the iceberg costs theory. Therefore, this paper constructs a conceptual framework of HSR affecting regional market integration in terms of market access, information flow, and substitution transportation. It also empirically tests the HSR effect of market integration using prefecture-level data from 2003 to 2013 in China. The results show that HSR has a significantly positive effect on China's regional market integration, and the three influencing mechanisms exist. However, the influence of HSR on regional market integration is different due to the heterogeneity of economic development and population scale.

Optimizing the Cooling System of High-Speed Train Environmental Wind Tunnels Using the Gene-Directed Change Genetic Algorithm.

Environmental wind tunnels play a crucial role in the research and development of high-speed railways. However, constructing and operating these wind tunnels requires significant resources, especially with respect to the cooling system, which serves as a vital subsystem. The cooling system utilizes an air compression refrigeration cycle and consists of multiple components. The efficient operation of these components, along with the adoption of appropriate strategies, greatly enhances the efficiency of the wind tunnel refrigeration system. Despite this, the existing methods for evaluating the refrigeration system do not fully capture the energy consumption of an air compression refrigeration system during practical use. To address this issue and effectively evaluate the wind tunnel refrigeration system, we propose using an exergoeconomic evaluation coefficient with experimental cycles to establish the system. This method incorporates the use of frequency coefficients and related parameters. By employing the newly developed evaluation coefficient as an objective function, we utilize the adaptive value-sharing congestion genetic algorithm to optimize the wind tunnel for high-speed trains. Furthermore, we compare the advantages and disadvantages of different optimization schemes. Traditional optimization methods prove inefficient because of the system's numerous variables and the presence of multiple peaks in the objective function. Inspired by the biogenetic breeding method, we introduce an optimization approach based on a specific gene mutation. This innovative method significantly reduces optimization time and improves efficiency by approximately 17%.

Research on elevated orbit noise propagation based on AI algorithm and propagation path analysis

With the rapid development of high-speed railway, noise reduction is becoming more and more important. At the same time, the study of elevated rail noise is also very important for the engineering field. The noise reduction of elevated rail noise is a part of the engineering construction, which is conducive to the economic development and the improvement of people’s life, and the reduction of noise has an impact on residents’ life. This article aims to investigate the analysis of the vibration and noise transmission path of the elevated railway. An optimized transmission path analysis method, which is based on the artificial intelligence algorithms, is used to optimize the path analysis, so as to trace the source of the noise and analyze the noise reduction. This method performs well in the analysis of vibration and noise of elevated railways. After this optimization, the contribution degree and frequency response function in the path analysis have better analysis performance. Through the actual measurement and analysis of the noise of the elevated railway, it can be proved that the traditional path method can better analyze the noise source. The environmental noise caused by high-speed trains passing bridges easily exceeds the acoustic environmental standards. After noise reduction, it can be reduced by about 5–10 dB.

Experimental study on the interface fatigue between track slab and self-compacting concrete for CRTS III slab track

With the rapid development of high-speed railways, the CRTS III slab track has become one of the most important track structures. The interface between the precast track slab and cast-in-place self-compacting concrete is easily damaged under fatigue loads. However, experimental research in this field is still relatively lacking. By performing static and fatigue splitting tensile tests, the study first obtained interface failure characteristics between the track slab and self-compacting concrete. Most of the interface failures were mortar failures and mortar-aggregate bond failures, and only a few were aggregate failures. Then, the evolution law of interface strain was analyzed. The interface strain was large in the middle and small on both sides. The change of interface strain with fatigue life ratio was divided into three stages: rapid growth, stable growth, and unstable growth stages. Moreover, the S-N curve of the interface was obtained. Finally, based on the residual strain, an interface fatigue damage model was established to reveal the evolution law of damage variables with fatigue life ratio under different stress levels. This study makes up for the insufficiency of current interface damage research on CRTS III slab track and provides the reference for the subsequent numerical simulation and engineering application.

Momentary ride comfort evaluation of high-speed trains based on feature selection and gated recurrent unit network

With the rapid development of high-speed railways, momentary ride comfort related to temporary excitation is becoming an important concern of the corresponding technology development. This paper proposes a method for momentary ride comfort evaluation, where subjective and objective evaluations are related with each other by means of feature selection and gated recurrent unit (GRU) network. In terms of the concept of maximum information coefficient and the idea of max-relevance and min-redundancy, a feature selection algorithm, MIC-mRMR, is implemented for multi-channel selection. A data augmentation based on down-sampling and channel replacement is designed to enlarge the dataset size, and the short-time Fourier transform is adopted to effectively extract the time-frequency characteristics of the objective measurement signal. A GRU model is then constructed for subjective evaluation according to measured vibration data. Objective experiments and subjective evaluation were conducted on a specially designed comprehensive inspection train, where the proposed methods are applied and validated. It is thus demonstrated that the proposed methods are effective in evaluating the momentary ride comfort of high-speed trains.

Template-based knowledge reuse method for generating high-speed railway virtual construction scenes

ABSTRACT Virtual construction has become an important approach to the high-quality development of high-speed railways, but existing methods have problems such as low efficiency in generating virtual construction scenes and the inability to reuse construction knowledge. To support the rapid visual representation of multiple types of construction processes and construction methods, a template-based knowledge reuse method is proposed. The method includes using a component-based modeling mode to build body structure models of a high-speed railway project and generate a 3D scene; decomposing the construction process and building a construction process knowledge base; establishing joint linkage models of construction machinery and forming a construction method knowledge template; and fusing multiple types of information according to a time sequence to visualize the construction process. Based on the template-based knowledge reuse method, a prototype system was developed, and virtual construction experiments were carried out. The results show that this method achieves the reuse of construction knowledge at different levels including construction machinery level, construction method level, and work site level. Compared with animation software for virtual construction, this method improves the production efficiency by 87%. Moreover, this method can provide a multilevel knowledge reuse scheme for diversified virtual construction.

Progress of research on evaluation indicators and standards about high-speed train comfort

The rapid development of high-speed railway in China has proposed higher requests for the comfort level of high-speed trains. However, there is no internationally unified evaluation criterion for high-speed train comfort currently, which therefore substantially affects the comparability and standardization of research results for high-speed train comfort. This paper systematically reviews the research literature about evaluation indicators and standards related to high-speed train comfort, and finds that there is currently no unified definition, evaluation indicators, as well as evaluation criterion for high-speed train comfort. Most current evaluation criteria are based on a single indicator. Some indicators are simultaneously developed by different apartments and differ between each other, and there is no comprehensive indicator or criteria for high-speed train comfort, restricting the comparison of high-speed train comfort across regions. It is recommended that the administrative department of high-speed railroad in China should organize experts to establish a unified definition of high-speed train comfort, comprehensive evaluation indicators and relevant judgment criteria for high-speed train comfort, in face of the rapid development and globalization of high-speed trains.

Energy Efficient Train-Ground mmWave Mobile Relay System for High Speed Railways

The rapid development of high-speed railways (HSRs) puts forward high requirements on the corresponding communication system. Millimeter wave (mmWave) can be a promising solution due to its wide bandwidth, narrow beams, and rich spectrum resources. However, with the large number of antenna elements employed, energy-efficient solutions at mmWave frequencies are in great demand. Based on a mmWave HSR communication system with multiple mobile relays (MRs) on top of the train, a dynamic power-control scheme for train-ground communications is proposed. The scheme follows the regular movement characteristics of high-speed trains and considers three phases of train movement: the train enters the cell, all MRs are covered in the cell, and the train leaves the cell. The transmit power is further refined according to the number of MRs in the cell and the distance between the train and the remote radio head. By minimizing energy consumption under the constraints of the transmitted data and transmit power budget, the transmit power is allocated to multiple MRs through the multiplier punitive function-based algorithm. Comprehensive simulation results, where the velocity estimation error is taken into account, are provided to demonstrate the effectiveness of the proposed scheme over several baseline schemes.

A decision model for high-speed railway express systems

With the rapid development of high-speed railway (HSR) networks, HSR express systems are becoming one of the most promising logistics systems. Such systems rely on road transportation to connect customers and railway stations in the HSR networks. HSR express systems also provide four main freight services such as arriving today, arriving the next morning, arriving the next day, arriving the day after tomorrow. This paper investigates a network planning and freight allocation problem for HSR express systems that considers decisions on intermodal station selection, vehicle assignment in road transportation, and freight flow organization. We also take into account factors such as the varying demand for different types of freight services and the uncertain capacity of high-speed trains in various scenarios. A two-stage stochastic programming model is proposed to minimize the total operational cost, which consists of fixed costs and variable costs, in random scenarios. To solve the problem, a metaheuristic algorithm is proposed that is validated by numerical experiments. Some sensitivity analysis on numerical experiments and a case study on the high-speed railway express systems of the China Railway Nanchang Group are conducted, the results of which yield useful managerial insights for practitioners.

The politics of military megaprojects: discursive struggles in Canadian and Australian naval shipbuilding strategies

AbstractLarge-scale military platform procurement is an essential but understudied component of the policy studies of megaprojects. Procurement decisions in this area, from ships to aircraft, are examples of a specific type of often very expensive purchases which feature complex multi-actor and multiyear processes characterized by high degrees of conflict between actors over purchases and planning horizons. This study of military procurement efforts of this type demonstrates the importance of maintaining policy ‘alignment’ between governments and service providers for successful megaproject procurement to occur and suggests several strategies for accomplishing this that can be applied to similar large-scale but nondefense-related projects, ranging from hydroelectric dams to high-speed railway development.