Inclusion has an important effect on quality of high speed rail steel. In consideration of the lower acceptance percentage of the inclusion and its constraint against the requirement for large scale production of 350 ...Inclusion has an important effect on quality of high speed rail steel. In consideration of the lower acceptance percentage of the inclusion and its constraint against the requirement for large scale production of 350 km/h high speed rail steel in Panzhihua Iron and Steel （Group） Co,the technology of nonmetallic inclusion control for 350 km/h high speed rail steel was studied. An optimized model of the argon-blowing in ladle furnace （LF）,the control of the components of the ladle slag,and the technique of calcium treatment for the molten steel was brought forward. Using the researched technology,the removal ratio of the inclusion was increased and the components,distribution,and shape of the inclusion in the rail steel were changed,which resulted in a reduction in the average total oxygen content to 10.17×10^-6 and an increase in the comprehensive acceptance percentage of the nonmetallic inclusion from 48.21% to 98.1%. Test has shown that this metallurgical technology can meet the requirement for large scale production of 350 km/h high speed steel in Panzhihua Iron and Steel （Group） Co.展开更多
The construction and operation of high-speed rail（HSR）grid within the past two decades in China,in terms of the scale,may be possibly comparable to any national-wide construction in the history of China,even the Gre...The construction and operation of high-speed rail（HSR）grid within the past two decades in China,in terms of the scale,may be possibly comparable to any national-wide construction in the history of China,even the Great Wall.By counting railways with commercial train service at the speed of200 km/h,China has the world’s longest HSR network with over 19 369.8 km of track in service today and this number展开更多
As High Speed Rail(HSR)has proliferated globally,so has a related research field dedicated to exploring and addressing its unique issues.Yet,studies to understand and classify the HSR research domain are limited.This ...As High Speed Rail(HSR)has proliferated globally,so has a related research field dedicated to exploring and addressing its unique issues.Yet,studies to understand and classify the HSR research domain are limited.This paper addresses the gap,using bibliometric analysis to identify future research areas and 20 candidate topics for literature review based on keyword analysis through VOSviewer.Article and review papers related to HSR published in the last 20 years(2003-2022)were retrieved from Scopus,and then analyzed to determine the split in knowledge between languages,the collaboration between countries and institutions,highly productive and cited journals,and research topics which have and have not been reviewed.Approximately 30%of the search results were published exclusively in Chinese,highlighting the importance of extending the evaluation to cover both languages.This is a novel aspect of the work,which has enabled the recognition of potential knowledge gaps.It is recommended that future reviews incorporate works in both languages,possibly through international collaboration.Institutions in China and other countries that are strong collaborators have been identified,as well as relevant,highly cited journals.展开更多
The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board...The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board train control system.To conduct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method combining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive validation.Firstly,a method for predicting equipment fault time targeting batch equipment is introduced.This method utilizes reliability statistics to construct a model of the remaining faultless operating time distribution considering uncertainty,thereby predicting the remaining faultless operating probability of the BTM unit.Secondly,considering the complexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text records,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is proposed.This method achieves better prediction results compared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of equipment.Finally,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional results.The results indicate that the predicted fault time and the actual fault time conform to a log-normal distribution,and the parameter estimation results are basically consistent,verifying the accuracy and effectiveness of the prediction results.The above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance costs and ensuring the safe operation of high-speed railway,thus having practical engineering value for preventive maintenance.展开更多
It was found that the steel plate in the composite plate in the WJ-8 fastener used in high speed rail is rusty. The objective of this study is to test the zinc coating of the steel plate. A literature review was condu...It was found that the steel plate in the composite plate in the WJ-8 fastener used in high speed rail is rusty. The objective of this study is to test the zinc coating of the steel plate. A literature review was conducted to identify the zinc coating techniques, and the companies that can provide different coating service was identified. A salt fog chamber was built that was in compliance with the ANSI B117 code, and the steel plates that were coated by the identified companies were tested using the salt fog chamber. The results indicated that the coating technique that had the best performance in preventing corrosion was the Greenkote plates with passivation. The galvanized option had the roughest coating layer, and it was the most reactive in the salt water solution. This makes it non-ideal for the dynamic rail environment because the increased friction of the plate could damage the supports, especially during extreme temperatures that would cause the rail to expand or contract. Greenkote with Phosphate and ArmorGalv also provided increased corrosion prevention with a smooth, strong finish, but it had more rust on the surface area than the Greenkote with ELU passivation. The ArmorGalv sample had more rust on the surface area than the Greenkote samples. This may not be a weakness in the ArmorGalv process;rather, it likely was the result of this particular sample not having the added protection of a colored coating.展开更多
Channel estimation is a well-known challenge for wireless orthogonal frequency division multiplexing(OFDM)communication systems with massive antennas on high speed rails(HSRs).This paper investigates this problem and ...Channel estimation is a well-known challenge for wireless orthogonal frequency division multiplexing(OFDM)communication systems with massive antennas on high speed rails(HSRs).This paper investigates this problem and design two practicable uplink and downlink channel estimators for orthogonal frequency division multiplexing(OFDM)communication systems with massive antenna arrays at base station on HSRs.Specifically,we first use pilots to estimate the initial angle of arrival(AoA)and channel gain information of each uplink path through discrete Fourier transform(DFT),and then refine the estimates via the angle rotation technique and suggested pilot design.Based on the uplink angel estimation,we design a new downlink channel estimator for frequency division duplexing(FDD)systems.Additionally,we derive the Cramér-Rao lower bounds(CRLBs)of the AoA and channel gain estimates.Finally,numerical results are provided to corroborate our proposed studies.展开更多
This paper assesses the impacts of high speed rail (HSR) development in the Yangtze River Delta (YRD) Megaregion, China. After giving an introduction and conducting a literature review, the paper proposes a pole-axis-...This paper assesses the impacts of high speed rail (HSR) development in the Yangtze River Delta (YRD) Megaregion, China. After giving an introduction and conducting a literature review, the paper proposes a pole-axis-network system (PANS) model guiding the entire study. On the one hand, the HSR projects in the YRD Megaregion are expected to generate significant efficiency-related transportation and non-transportation benefits. As a result, the spillover effects from Shanghai and other major cities (poles) will greatly promote the urban and regional developments along the major HSR corridors (axes), and the entire megaregion will become more integrated economically, socially, and culturally. But, on the other hand, the HSR projects will also create serious social and geographic inequity issues, which need to be addressed as soon as possible in a proper way. This empirical study confirms the PANS model proposed.展开更多
High speed rail systems have blossomed in technological advances since their debut in the 1960’s with the Japanese Shinkansen line. As miles upon miles of tracks increase around the world, bringing added mobility to ...High speed rail systems have blossomed in technological advances since their debut in the 1960’s with the Japanese Shinkansen line. As miles upon miles of tracks increase around the world, bringing added mobility to travelers while decreasing emissions, various technologies are leading the way to a faster tomorrow. This article explores the differences in what countries around the world are using to supply the next generation of travel modes. This paper details the differences in technological implementations from Asia, Europe, and North America. High speed rail systems are far more developed in other countries, especially China, and have required substantial government investment. The United States, with limited HSR development, stands to benefit from the technological advances of others and learn from the economic impacts of HSR in other countries.展开更多
This article contributes to a small but growing body of multi-sited and multi-scalar research on the Belt and Road Initiative.We focus on relations at the national,regional and international scales,and present origina...This article contributes to a small but growing body of multi-sited and multi-scalar research on the Belt and Road Initiative.We focus on relations at the national,regional and international scales,and present original research from China and Turkey,to show how the Istanbul-Ankara high-speed railway has served as a testing ground for China's Belt and Road Initiative(BRI).Its construction was initially funded by the European Investment Bank,but it is now part of the backbone of the Turkish Government's Middle Corridor plan which enhances west-east connectivity and integration with the Caucasus and Central Asia.We show that in contrast to multinational corporations from the OECD that seek to remain footloose,Chinese state-owned enterprises(SOEs)seek to adapt to,apprehend and ultimately shape local institutions.In the case of Turkey this proved difficult given its institutional alignment with the European Union.Thus,while the railway project was completed successfully by a consortium led by a Chinese SOE,Turkey's dynamic and complex regulatory environment discourages Chinese SOEs in the infrastructure sector.We conclude that the Turkish and Chinese governments are currently pursuing complementary territorial visions yet their cooperation is project-based and pragmatic.展开更多
High-speed rail(HSR) has formed a networked operational scale in China. Any internal or external disturbance may deviate trains’ operation from the planned schedules, resulting in primary delays or even cascading del...High-speed rail(HSR) has formed a networked operational scale in China. Any internal or external disturbance may deviate trains’ operation from the planned schedules, resulting in primary delays or even cascading delays on a network scale. Studying the delay propagation mechanism could help to improve the timetable resilience in the planning stage and realize cooperative rescheduling for dispatchers. To quickly and effectively predict the spatial-temporal range of cascading delays, this paper proposes a max-plus algebra based delay propagation model considering trains’ operation strategy and the systems’ constraints. A double-layer network based breadth-first search algorithm based on the constraint network and the timetable network is further proposed to solve the delay propagation process for different kinds of emergencies. The proposed model could deal with the delay propagation problem when emergencies occur in sections or stations and is suitable for static emergencies and dynamic emergencies. Case studies show that the proposed algorithm can significantly improve the computational efficiency of the large-scale HSR network. Moreover, the real operational data of China HSR is adopted to verify the proposed model, and the results show that the cascading delays can be timely and accurately inferred, and the delay propagation characteristics under three kinds of emergencies are unfolded.展开更多
Railway capacity has been extensively investigated for the purpose of utilizing rail infrastructure in a possible efficient strategy.Nevertheless,the estimation of high speed rail(HSR),which is different from common r...Railway capacity has been extensively investigated for the purpose of utilizing rail infrastructure in a possible efficient strategy.Nevertheless,the estimation of high speed rail(HSR),which is different from common railways in many aspects,is still a challenge work needed to be solved.Consequently,this work focuses on the capacity estimation of HSR corridor.The objectives and constraints are developed for the HSR with the consideration of passenger service level and buffer time uncertainty,and a two-stage optimization model is proposed.The first stage determines the optimal number of trains in terms of the passenger origin–destination demand,and the second stage is a multi-objective mixed integer programming(MO-MIP)aiming to estimate the optimal capacity usage.The branch-and-bound algorithm is extended and applied to the proposed model,and a case study is performed to Beijing–Shanghai HSR line.The optimal solution is obtained,and the sensitivity of the two objectives is analyzed.展开更多
The objective of this study was to quantify multimodal connectivity of HSR stations and its impact on ridership in four countries: France, Spain, Japan and China. In this study, multimodal connectivity is measured by ...The objective of this study was to quantify multimodal connectivity of HSR stations and its impact on ridership in four countries: France, Spain, Japan and China. In this study, multimodal connectivity is measured by the number of different modes of transportation connected to HSR stations, the number of installed arrival and departure facilities for each mode, the transfer time from connecting modes to boarding platforms at HSR stations, and the arrival time intervals of public transportation modes. Data were collected from HSR systems of these four countries. The relationship between ridership and the characteristics of multimodal connectivity was identified using regression models developed in this study. All the connectivity variables considered in this study influence ridership in these four countries in different ways. On the whole, bus, subway, and regional railroad services influence ridership significantly. For instance, the more bus services connected to the station, the higher the ridership. This trend is apparent in three of the four countries, France being the exception. Also, subway, light rail, and traditional rail are modes of high-capacity transportation. Their connection to HSR stations always implies high ridership for high-speed rail. The number of facilities also shows significant impacts on HSR ridership. For instance, the more bus and subway stops, and the more bicycle parking and taxi stands, the higher the ridership. Transfer time also has a significant influence.展开更多
The United States has taken initial steps toward developing a high speed rail(HSR)network,but the domestic workforce experience and institutional knowledge necessary for the planning,design,construction,and operations...The United States has taken initial steps toward developing a high speed rail(HSR)network,but the domestic workforce experience and institutional knowledge necessary for the planning,design,construction,and operations of HSR is underdeveloped.This paper describes and provides preliminary assessment of the High Speed Rail Learning System(HSRLS),a demonstration project that seeks to address gaps in HSR knowledge and skills in the US.The HSRLS developers designed an online education system to serve as a clearinghouse for railrelated information and content,connect teachers,trainers,and students at pre-,and postgraduate levels,and to collect demographic and professional information on groups and individuals interested in HSR.The paper explores the technology review,selection process,and content developed.Website visits and demographic information from over 4,000 unique individuals and 600 HSRLS course registrations are analyzed and assessed.展开更多
Traffic is an indispensable prerequisite for a tourism system. The ＂four vertical and four horizontal＂ HSR network represents an important milestone of the ＂traffic revolution＂ in China. It will affect the spatial...Traffic is an indispensable prerequisite for a tourism system. The ＂four vertical and four horizontal＂ HSR network represents an important milestone of the ＂traffic revolution＂ in China. It will affect the spatial pattern of tourism accessibility in Chinese cities, thus substan- tially increasing their power to attract tourists and their radiation force. This paper examines the evolution and spatial characteristics of the power to attract tourism of cities linked by China＇s HSR network by measuring the influence of accessibility of 338 HSR-linked cities using GIS analysis. The results show the following. （1） The accessibility of Chinese cities is optimized by the HSR network, whose spatial pattern of accessibility exhibits an obvious traf- fic direction and causes a high-speed rail-corridor effect. （2） The spatial pattern of tourism field strength in Chinese cities exhibits the dual characteristics of multi-center annular diver- gence and dendritic diffusion. Dendritic diffusion is particularly more obvious along the HSR line. The change rate of urban tourism field strength forms a high-value corridor along the HSR line and exhibits a spatial pattern of decreasing area from the center to the outer limit along the HSR line. （3） The influence of the higher and highest tourism field strength areas along the HSR line is most significant, and the number of cities that distribute into these two types of tourism field strengths significantly increases： their area expands by more than 100% HSR enhances the tourism field strength value of regional central cities, and the radiation range of tourism attraction extends along the HSR line.展开更多
The rapid development of high-speed rail （HSR） and air transport in China has encouraged research on the spatial effects and safety of these two modes of transport, and on the competition between them. We report her...The rapid development of high-speed rail （HSR） and air transport in China has encouraged research on the spatial effects and safety of these two modes of transport, and on the competition between them. We report here an investigation of the effects of competi- tion between HSR and air transport in China from a geographical perspective. The spatial service hinterlands for HSR and air transport accessible within one and two hours by road transport were investigated using a method based on a geographical information system and the overlapping service hinterlands of HSR and air transport were established. A city with both HSR stations and airports, or that was accessible to HSR stations and airports within a certain travel time by road transport, was defined as the overlapping market. The spatial effects of competition between HSR and air transport at present and in the future were then studied with respect to the planned HSR network and airports. The results showed that both HSR and air transport tend to serve areas with high population densities and well-developed econo- mies and in 2012 most of the population and GDP in China were accessible within two hours by road transport to an HSR station or airport. -the different technical and economic charac- teristics of HSR and air transport determine the advantage markets. Spatially, the service hinterland of HSR mainly focuses on urban agglomerations and economic corridors in the eastern and central regions, whereas air transport has a competitive advantage in the more inaccessible western region of China. The overlapping market of HSR and air transport will become increasingly large in the future and cities with a population of over one million and cities within 30 km to both airports and HSR stations will become the major competitive markets. Considering the cost of construction and the number of passengers required for economic operation, as well as the competition with air transport, it is suggested that the construction of some HSR projects in the western region of China should be canceled or slowed down.展开更多
Cross-line trains, as a link between high-speed and conventional rail networks, will increase the complexity of transport organization and lead to significant challenges in dispatch coordination between the two system...Cross-line trains, as a link between high-speed and conventional rail networks, will increase the complexity of transport organization and lead to significant challenges in dispatch coordination between the two systems. Based on the characteristics of high-speed transport organization, this paper deals with the necessity of dispatch coordination between high-speed and conventional lines from the following two perspectives： the operation of cross-line trains and work coordination in connection stations. An adjustment model for the operation of high-speed trains, taking cross-line trains into account, is established. Finally, the dispatch system is described in terms of construction and process. Methods for organizing dispatch are proposed, and the processes of coordination adjustment under normal and unexpected situations are analyzed. The discussion in this paper may serve as a theoretical basis for the development of high-speed rail dispatch systems.展开更多
Based on the vehicle track coupling dynamics theory, a new spatial dynamic numerical model of vehicle track subgrade coupling system was established considering the interaction among different structural layers in the...Based on the vehicle track coupling dynamics theory, a new spatial dynamic numerical model of vehicle track subgrade coupling system was established considering the interaction among different structural layers in the subgrade system. The dynamic responses of the coupled system were analyzed when the speed of train was 350 km/h and the transition was filled with graded broken stones mixed with 5% cement. The results indicate that the setting form of bridge-approach embankment section has little effect on the dynamic responses, thus designers can choose it on account of the practical circumstances. Because the location about 5 m from the bridge abutment has the greatest deformation, the stiffness within 0 5 m zone behind the abutment should be specially designed. The results of the study from vehicle track dynamics show that the maximum allowable track deflection angle should be 0.09% and the coefficient of subgrade reaction(K30) is greater than 190 MPa within the 0 5 m zone behind the abutment and greater than 150 MPa in other zones.展开更多
The rapid development of high-speed rail（HSR） is influencing regional development, regional structure, commuting, and regional integration. East Asia is the region with the world＇s first and largest current operati...The rapid development of high-speed rail（HSR） is influencing regional development, regional structure, commuting, and regional integration. East Asia is the region with the world＇s first and largest current operating and planned HSR network. In this paper, we examine the evolutionary mechanism and impacts on the transport circle and accessibility of HSR in East Asia. The results indicate that the HSR network first follows a ＂core-core＂ model and then forms a corridor in Japan, South Korea, and China Taiwan, but then forms a complete network in China Mainland. The current operating HSR lines are mostly distributed in regions with developed economies and dense populations, and more than half of the population and GDP in China can be served by HSR within 1 hour＇s travel time. The planned HSR network will expand to the western region of China and Japan and the southern region of South Korea. The development of the current operating and planned HSR network considerably enlarges the transport circle of core cities, especially cities along trunk HSR lines. This 1 h transport circle of core cities has formed continuous regions in the Yangtze River Delta, the Pearl River Delta, Tokyo, Seoul, and along trunk HSR lines. The HSR network will bring about substantial improvement in accessiblity, but also increase the inequality of nodal accessibility in China Mainland. Spatially, the spatial patterns of the weighted shortest travel time of cities in China Mainland, Japan, and South Korea all present the ＂core-peripheral structure＂, taking Zhengzhou, Tokyo, and Seoul, respectively, as core cities, and cities located along the trunk HSR lines gain large improvement in accessibility.展开更多
Rail wear is one of the main reasons for reducing the service life of high-speed railway turnouts in China. The rail wear characteristics of high-speed railway turnouts are influenced by a large number of input parame...Rail wear is one of the main reasons for reducing the service life of high-speed railway turnouts in China. The rail wear characteristics of high-speed railway turnouts are influenced by a large number of input parameters of the complex train-turnout system. To reproduce the actual operation conditions of railway turnouts, random distributions of these inputs need to be considered in rail wear simulation. For a given nominal layout of the high-speed railway turnout, 19 input parameters for rail wear simulation in high-speed railway turnouts are investigated based on orthogonal design of experiment. Three dynamic responses(wheel-rail friction work, normal contact force and size of contact patch) are defined as observed values and the significant factors(direction of passage, axle load, running speed, friction coefficient, and wheel and rail profiles) are determined by two unreplicated saturated factorial design methods, including the half-normal probability plot method and Dong 93 method. As part of the associated rail wear simulation, the influence of the wear models and the local elastic deformation on the rail wear was separately investigated. The calculation results for the wear models are quite different, especially for large creep mode. The local elastic deformation has a large effect on the sliding speed and rail wear and needs to be considered in the rail wear simulation.展开更多
This paper presents methods for monitoring frost heave, device requirements, testing principals, and data analysis re- quirements, such as manual leveling observation, automatic monitoring （frost heave, frost depth, ...This paper presents methods for monitoring frost heave, device requirements, testing principals, and data analysis re- quirements, such as manual leveling observation, automatic monitoring （frost heave, frost depth, and moisture）, track dynamic detection, and track status detection. We focused on the requirements of subgrade frost heave monitoring for high speed railways, and the relationship of different monitoring methods during different phases of the railway. The com- prehensive monitoring system of high speed railway subgrade frost heave provided the technical support for dynamic design during construction and safe operation of the rail system.展开更多
基金Sponsored by Key Technologies Research and Development Program for the 10th Five-Year Plan (2004BA317B)
文摘Inclusion has an important effect on quality of high speed rail steel. In consideration of the lower acceptance percentage of the inclusion and its constraint against the requirement for large scale production of 350 km/h high speed rail steel in Panzhihua Iron and Steel （Group） Co,the technology of nonmetallic inclusion control for 350 km/h high speed rail steel was studied. An optimized model of the argon-blowing in ladle furnace （LF）,the control of the components of the ladle slag,and the technique of calcium treatment for the molten steel was brought forward. Using the researched technology,the removal ratio of the inclusion was increased and the components,distribution,and shape of the inclusion in the rail steel were changed,which resulted in a reduction in the average total oxygen content to 10.17×10^-6 and an increase in the comprehensive acceptance percentage of the nonmetallic inclusion from 48.21% to 98.1%. Test has shown that this metallurgical technology can meet the requirement for large scale production of 350 km/h high speed steel in Panzhihua Iron and Steel （Group） Co.
文摘The construction and operation of high-speed rail（HSR）grid within the past two decades in China,in terms of the scale,may be possibly comparable to any national-wide construction in the history of China,even the Great Wall.By counting railways with commercial train service at the speed of200 km/h,China has the world’s longest HSR network with over 19 369.8 km of track in service today and this number
文摘As High Speed Rail(HSR)has proliferated globally,so has a related research field dedicated to exploring and addressing its unique issues.Yet,studies to understand and classify the HSR research domain are limited.This paper addresses the gap,using bibliometric analysis to identify future research areas and 20 candidate topics for literature review based on keyword analysis through VOSviewer.Article and review papers related to HSR published in the last 20 years(2003-2022)were retrieved from Scopus,and then analyzed to determine the split in knowledge between languages,the collaboration between countries and institutions,highly productive and cited journals,and research topics which have and have not been reviewed.Approximately 30%of the search results were published exclusively in Chinese,highlighting the importance of extending the evaluation to cover both languages.This is a novel aspect of the work,which has enabled the recognition of potential knowledge gaps.It is recommended that future reviews incorporate works in both languages,possibly through international collaboration.Institutions in China and other countries that are strong collaborators have been identified,as well as relevant,highly cited journals.
基金supported by the Integrated Rail Transit Dispatch Control and Intermodal Transport Service Technology Project(Grant No.2022YFB4300500).
文摘The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board train control system.To conduct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method combining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive validation.Firstly,a method for predicting equipment fault time targeting batch equipment is introduced.This method utilizes reliability statistics to construct a model of the remaining faultless operating time distribution considering uncertainty,thereby predicting the remaining faultless operating probability of the BTM unit.Secondly,considering the complexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text records,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is proposed.This method achieves better prediction results compared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of equipment.Finally,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional results.The results indicate that the predicted fault time and the actual fault time conform to a log-normal distribution,and the parameter estimation results are basically consistent,verifying the accuracy and effectiveness of the prediction results.The above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance costs and ensuring the safe operation of high-speed railway,thus having practical engineering value for preventive maintenance.
文摘It was found that the steel plate in the composite plate in the WJ-8 fastener used in high speed rail is rusty. The objective of this study is to test the zinc coating of the steel plate. A literature review was conducted to identify the zinc coating techniques, and the companies that can provide different coating service was identified. A salt fog chamber was built that was in compliance with the ANSI B117 code, and the steel plates that were coated by the identified companies were tested using the salt fog chamber. The results indicated that the coating technique that had the best performance in preventing corrosion was the Greenkote plates with passivation. The galvanized option had the roughest coating layer, and it was the most reactive in the salt water solution. This makes it non-ideal for the dynamic rail environment because the increased friction of the plate could damage the supports, especially during extreme temperatures that would cause the rail to expand or contract. Greenkote with Phosphate and ArmorGalv also provided increased corrosion prevention with a smooth, strong finish, but it had more rust on the surface area than the Greenkote with ELU passivation. The ArmorGalv sample had more rust on the surface area than the Greenkote samples. This may not be a weakness in the ArmorGalv process;rather, it likely was the result of this particular sample not having the added protection of a colored coating.
基金National S&T Project 2018YJS036.This study is supported in part by Key Laboratory of Universal Wireless Communications(BUPT),Ministry of Education,P.R.China(No.KFKT-2018104)by the Natural Science Foundation of China(NSFC,No.61571037,61871026,61961130391,and U1834210)+2 种基金NSFC Outstanding Youth(No.61725101)National Key R&D Program of China under Grant 2016YFE0200900the Royal Society Newton Advanced Fellowship under Grant NA191006.
文摘Channel estimation is a well-known challenge for wireless orthogonal frequency division multiplexing(OFDM)communication systems with massive antennas on high speed rails(HSRs).This paper investigates this problem and design two practicable uplink and downlink channel estimators for orthogonal frequency division multiplexing(OFDM)communication systems with massive antenna arrays at base station on HSRs.Specifically,we first use pilots to estimate the initial angle of arrival(AoA)and channel gain information of each uplink path through discrete Fourier transform(DFT),and then refine the estimates via the angle rotation technique and suggested pilot design.Based on the uplink angel estimation,we design a new downlink channel estimator for frequency division duplexing(FDD)systems.Additionally,we derive the Cramér-Rao lower bounds(CRLBs)of the AoA and channel gain estimates.Finally,numerical results are provided to corroborate our proposed studies.
文摘This paper assesses the impacts of high speed rail (HSR) development in the Yangtze River Delta (YRD) Megaregion, China. After giving an introduction and conducting a literature review, the paper proposes a pole-axis-network system (PANS) model guiding the entire study. On the one hand, the HSR projects in the YRD Megaregion are expected to generate significant efficiency-related transportation and non-transportation benefits. As a result, the spillover effects from Shanghai and other major cities (poles) will greatly promote the urban and regional developments along the major HSR corridors (axes), and the entire megaregion will become more integrated economically, socially, and culturally. But, on the other hand, the HSR projects will also create serious social and geographic inequity issues, which need to be addressed as soon as possible in a proper way. This empirical study confirms the PANS model proposed.
文摘High speed rail systems have blossomed in technological advances since their debut in the 1960’s with the Japanese Shinkansen line. As miles upon miles of tracks increase around the world, bringing added mobility to travelers while decreasing emissions, various technologies are leading the way to a faster tomorrow. This article explores the differences in what countries around the world are using to supply the next generation of travel modes. This paper details the differences in technological implementations from Asia, Europe, and North America. High speed rail systems are far more developed in other countries, especially China, and have required substantial government investment. The United States, with limited HSR development, stands to benefit from the technological advances of others and learn from the economic impacts of HSR in other countries.
基金Strategic Priority Research Program of Chinese Academy of Sciences,No.XDA20010102National Natural Science Foundation of China,No.41871115,No.41530751British Academy Newton Advanced Fellowship,No.NAF2R2/100172。
文摘This article contributes to a small but growing body of multi-sited and multi-scalar research on the Belt and Road Initiative.We focus on relations at the national,regional and international scales,and present original research from China and Turkey,to show how the Istanbul-Ankara high-speed railway has served as a testing ground for China's Belt and Road Initiative(BRI).Its construction was initially funded by the European Investment Bank,but it is now part of the backbone of the Turkish Government's Middle Corridor plan which enhances west-east connectivity and integration with the Caucasus and Central Asia.We show that in contrast to multinational corporations from the OECD that seek to remain footloose,Chinese state-owned enterprises(SOEs)seek to adapt to,apprehend and ultimately shape local institutions.In the case of Turkey this proved difficult given its institutional alignment with the European Union.Thus,while the railway project was completed successfully by a consortium led by a Chinese SOE,Turkey's dynamic and complex regulatory environment discourages Chinese SOEs in the infrastructure sector.We conclude that the Turkish and Chinese governments are currently pursuing complementary territorial visions yet their cooperation is project-based and pragmatic.
基金supported by the National Natural Science Foundation of China (U1834211, 61925302, 62103033)the Open Research Fund of the State Key Laboratory for Management and Control of Complex Systems (20210104)。
文摘High-speed rail(HSR) has formed a networked operational scale in China. Any internal or external disturbance may deviate trains’ operation from the planned schedules, resulting in primary delays or even cascading delays on a network scale. Studying the delay propagation mechanism could help to improve the timetable resilience in the planning stage and realize cooperative rescheduling for dispatchers. To quickly and effectively predict the spatial-temporal range of cascading delays, this paper proposes a max-plus algebra based delay propagation model considering trains’ operation strategy and the systems’ constraints. A double-layer network based breadth-first search algorithm based on the constraint network and the timetable network is further proposed to solve the delay propagation process for different kinds of emergencies. The proposed model could deal with the delay propagation problem when emergencies occur in sections or stations and is suitable for static emergencies and dynamic emergencies. Case studies show that the proposed algorithm can significantly improve the computational efficiency of the large-scale HSR network. Moreover, the real operational data of China HSR is adopted to verify the proposed model, and the results show that the cascading delays can be timely and accurately inferred, and the delay propagation characteristics under three kinds of emergencies are unfolded.
基金The Ministry of Transport Construction Projects in Science and Technology(No.2015318223010).
文摘Railway capacity has been extensively investigated for the purpose of utilizing rail infrastructure in a possible efficient strategy.Nevertheless,the estimation of high speed rail(HSR),which is different from common railways in many aspects,is still a challenge work needed to be solved.Consequently,this work focuses on the capacity estimation of HSR corridor.The objectives and constraints are developed for the HSR with the consideration of passenger service level and buffer time uncertainty,and a two-stage optimization model is proposed.The first stage determines the optimal number of trains in terms of the passenger origin–destination demand,and the second stage is a multi-objective mixed integer programming(MO-MIP)aiming to estimate the optimal capacity usage.The branch-and-bound algorithm is extended and applied to the proposed model,and a case study is performed to Beijing–Shanghai HSR line.The optimal solution is obtained,and the sensitivity of the two objectives is analyzed.
文摘The objective of this study was to quantify multimodal connectivity of HSR stations and its impact on ridership in four countries: France, Spain, Japan and China. In this study, multimodal connectivity is measured by the number of different modes of transportation connected to HSR stations, the number of installed arrival and departure facilities for each mode, the transfer time from connecting modes to boarding platforms at HSR stations, and the arrival time intervals of public transportation modes. Data were collected from HSR systems of these four countries. The relationship between ridership and the characteristics of multimodal connectivity was identified using regression models developed in this study. All the connectivity variables considered in this study influence ridership in these four countries in different ways. On the whole, bus, subway, and regional railroad services influence ridership significantly. For instance, the more bus services connected to the station, the higher the ridership. This trend is apparent in three of the four countries, France being the exception. Also, subway, light rail, and traditional rail are modes of high-capacity transportation. Their connection to HSR stations always implies high ridership for high-speed rail. The number of facilities also shows significant impacts on HSR ridership. For instance, the more bus and subway stops, and the more bicycle parking and taxi stands, the higher the ridership. Transfer time also has a significant influence.
文摘The United States has taken initial steps toward developing a high speed rail(HSR)network,but the domestic workforce experience and institutional knowledge necessary for the planning,design,construction,and operations of HSR is underdeveloped.This paper describes and provides preliminary assessment of the High Speed Rail Learning System(HSRLS),a demonstration project that seeks to address gaps in HSR knowledge and skills in the US.The HSRLS developers designed an online education system to serve as a clearinghouse for railrelated information and content,connect teachers,trainers,and students at pre-,and postgraduate levels,and to collect demographic and professional information on groups and individuals interested in HSR.The paper explores the technology review,selection process,and content developed.Website visits and demographic information from over 4,000 unique individuals and 600 HSRLS course registrations are analyzed and assessed.
基金Foundation： National Natural Science Foundation of China, No. 41271134
文摘Traffic is an indispensable prerequisite for a tourism system. The ＂four vertical and four horizontal＂ HSR network represents an important milestone of the ＂traffic revolution＂ in China. It will affect the spatial pattern of tourism accessibility in Chinese cities, thus substan- tially increasing their power to attract tourists and their radiation force. This paper examines the evolution and spatial characteristics of the power to attract tourism of cities linked by China＇s HSR network by measuring the influence of accessibility of 338 HSR-linked cities using GIS analysis. The results show the following. （1） The accessibility of Chinese cities is optimized by the HSR network, whose spatial pattern of accessibility exhibits an obvious traf- fic direction and causes a high-speed rail-corridor effect. （2） The spatial pattern of tourism field strength in Chinese cities exhibits the dual characteristics of multi-center annular diver- gence and dendritic diffusion. Dendritic diffusion is particularly more obvious along the HSR line. The change rate of urban tourism field strength forms a high-value corridor along the HSR line and exhibits a spatial pattern of decreasing area from the center to the outer limit along the HSR line. （3） The influence of the higher and highest tourism field strength areas along the HSR line is most significant, and the number of cities that distribute into these two types of tourism field strengths significantly increases： their area expands by more than 100% HSR enhances the tourism field strength value of regional central cities, and the radiation range of tourism attraction extends along the HSR line.
基金National Natural Science Foundation of China, No. 41371143 No. 41171107 Programme of Bingwei Excellent Young Scientists of the Institute of Geographic Sciences and Natural Resources Research, CAS, No.2011RC201.
文摘The rapid development of high-speed rail （HSR） and air transport in China has encouraged research on the spatial effects and safety of these two modes of transport, and on the competition between them. We report here an investigation of the effects of competi- tion between HSR and air transport in China from a geographical perspective. The spatial service hinterlands for HSR and air transport accessible within one and two hours by road transport were investigated using a method based on a geographical information system and the overlapping service hinterlands of HSR and air transport were established. A city with both HSR stations and airports, or that was accessible to HSR stations and airports within a certain travel time by road transport, was defined as the overlapping market. The spatial effects of competition between HSR and air transport at present and in the future were then studied with respect to the planned HSR network and airports. The results showed that both HSR and air transport tend to serve areas with high population densities and well-developed econo- mies and in 2012 most of the population and GDP in China were accessible within two hours by road transport to an HSR station or airport. -the different technical and economic charac- teristics of HSR and air transport determine the advantage markets. Spatially, the service hinterland of HSR mainly focuses on urban agglomerations and economic corridors in the eastern and central regions, whereas air transport has a competitive advantage in the more inaccessible western region of China. The overlapping market of HSR and air transport will become increasingly large in the future and cities with a population of over one million and cities within 30 km to both airports and HSR stations will become the major competitive markets. Considering the cost of construction and the number of passengers required for economic operation, as well as the competition with air transport, it is suggested that the construction of some HSR projects in the western region of China should be canceled or slowed down.
基金one of the key parts of an NNFF (Na-tional Natural Science Foundation) project under grant 60776827:‘Train network operation program with optimization theory and method research’meanwhile is the key research in ‘Study of optimization method and adjustment theory of high-speed train operation’ supported by the Doctoral Program Foundation of Ministry of Education under grant 20090184110011
文摘Cross-line trains, as a link between high-speed and conventional rail networks, will increase the complexity of transport organization and lead to significant challenges in dispatch coordination between the two systems. Based on the characteristics of high-speed transport organization, this paper deals with the necessity of dispatch coordination between high-speed and conventional lines from the following two perspectives： the operation of cross-line trains and work coordination in connection stations. An adjustment model for the operation of high-speed trains, taking cross-line trains into account, is established. Finally, the dispatch system is described in terms of construction and process. Methods for organizing dispatch are proposed, and the processes of coordination adjustment under normal and unexpected situations are analyzed. The discussion in this paper may serve as a theoretical basis for the development of high-speed rail dispatch systems.
基金Project(41030742) supported by the National Natural Science Foundation of ChinaProject(2009G010-c) supported by the Technological Research and Development Programs of the Ministry of Railways,China
文摘Based on the vehicle track coupling dynamics theory, a new spatial dynamic numerical model of vehicle track subgrade coupling system was established considering the interaction among different structural layers in the subgrade system. The dynamic responses of the coupled system were analyzed when the speed of train was 350 km/h and the transition was filled with graded broken stones mixed with 5% cement. The results indicate that the setting form of bridge-approach embankment section has little effect on the dynamic responses, thus designers can choose it on account of the practical circumstances. Because the location about 5 m from the bridge abutment has the greatest deformation, the stiffness within 0 5 m zone behind the abutment should be specially designed. The results of the study from vehicle track dynamics show that the maximum allowable track deflection angle should be 0.09% and the coefficient of subgrade reaction(K30) is greater than 190 MPa within the 0 5 m zone behind the abutment and greater than 150 MPa in other zones.
基金National Natural Science Foundation of China,No.41171107,No.41371143,No.4401121
文摘The rapid development of high-speed rail（HSR） is influencing regional development, regional structure, commuting, and regional integration. East Asia is the region with the world＇s first and largest current operating and planned HSR network. In this paper, we examine the evolutionary mechanism and impacts on the transport circle and accessibility of HSR in East Asia. The results indicate that the HSR network first follows a ＂core-core＂ model and then forms a corridor in Japan, South Korea, and China Taiwan, but then forms a complete network in China Mainland. The current operating HSR lines are mostly distributed in regions with developed economies and dense populations, and more than half of the population and GDP in China can be served by HSR within 1 hour＇s travel time. The planned HSR network will expand to the western region of China and Japan and the southern region of South Korea. The development of the current operating and planned HSR network considerably enlarges the transport circle of core cities, especially cities along trunk HSR lines. This 1 h transport circle of core cities has formed continuous regions in the Yangtze River Delta, the Pearl River Delta, Tokyo, Seoul, and along trunk HSR lines. The HSR network will bring about substantial improvement in accessiblity, but also increase the inequality of nodal accessibility in China Mainland. Spatially, the spatial patterns of the weighted shortest travel time of cities in China Mainland, Japan, and South Korea all present the ＂core-peripheral structure＂, taking Zhengzhou, Tokyo, and Seoul, respectively, as core cities, and cities located along the trunk HSR lines gain large improvement in accessibility.
基金Projects(51425804,51378439,51608459)supported by the National Natural Science Foundation of ChinaProjects(U1334203,U1234201)supported by the Key Project of the China’s High-Speed Railway United Fund+1 种基金Project(2016M590898)supported by China Postdoctoral Science FoundationProject(2014GZ0009)supported by Sichuan Provinial Science and Technology support Program,China
文摘Rail wear is one of the main reasons for reducing the service life of high-speed railway turnouts in China. The rail wear characteristics of high-speed railway turnouts are influenced by a large number of input parameters of the complex train-turnout system. To reproduce the actual operation conditions of railway turnouts, random distributions of these inputs need to be considered in rail wear simulation. For a given nominal layout of the high-speed railway turnout, 19 input parameters for rail wear simulation in high-speed railway turnouts are investigated based on orthogonal design of experiment. Three dynamic responses(wheel-rail friction work, normal contact force and size of contact patch) are defined as observed values and the significant factors(direction of passage, axle load, running speed, friction coefficient, and wheel and rail profiles) are determined by two unreplicated saturated factorial design methods, including the half-normal probability plot method and Dong 93 method. As part of the associated rail wear simulation, the influence of the wear models and the local elastic deformation on the rail wear was separately investigated. The calculation results for the wear models are quite different, especially for large creep mode. The local elastic deformation has a large effect on the sliding speed and rail wear and needs to be considered in the rail wear simulation.
基金support from the China Railways Corporation research project entitled"The technical tests for the high speed railway subgrade frost heave prevention in the alpine"(Project No.Z2013-038),"The long term observation of frost-heave technology for Ha-Da high-speed railway during the operation"(Project No.Z2012-062)+2 种基金Optimal design for high-speed railway subgrade structure under different grade and environment(Project No.2014G003-A)support from the railway scientific and technological research and development center called"The mechanism and evolution rule of the graded gravel under freeze and thawing cycles for the high speed railway"(Project No.J2014G003)The disease control technology and equipment of gradating gravel in surface layer of subgrade bed(Project No.2013YJ032)
文摘This paper presents methods for monitoring frost heave, device requirements, testing principals, and data analysis re- quirements, such as manual leveling observation, automatic monitoring （frost heave, frost depth, and moisture）, track dynamic detection, and track status detection. We focused on the requirements of subgrade frost heave monitoring for high speed railways, and the relationship of different monitoring methods during different phases of the railway. The com- prehensive monitoring system of high speed railway subgrade frost heave provided the technical support for dynamic design during construction and safe operation of the rail system.
