Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria.However,while rail transport continues to enjoy relative importance in t...Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria.However,while rail transport continues to enjoy relative importance in terms of investment,growth and contribution to the national economy in several countries,it has suffered and declined(in terms of modal share contribution which has led to decreased patronage)in Nigeria.However,there are new developments and investment on rail and some measures are being put in place to revive the Nigerian rail transport system.As these new developments and rehabilitations are going on,it will be imperative to know what the users/customers think as well,so that they are not left out because under normal circumstances,customers need transport services and not rail transport services.Therefore,if they were not satisfied with rail transport services they would simply turn to other modes of transport.As part of an on-going PhD research project,this paper focuses on the perceptions of Nigerian rail transport users/customers regarding the quality of rail services provided.Data was collected by the use of structured/semi-structured questionnaires,which were distributed,to the respondents.The study sample included 474 respondents between the age range of 20-70 out of which just 21(4.4%)have used rail transport;this low patronage figure is as a result of the long time neglect of the Nigerian rail transport system while 474(100%)of the correspondents use road transport daily which has led to an increasing pressure on road transport and infrastructures.Data was collected respectively from the following cities:Lagos,Warri,Ughelli and Benin.展开更多
The sugarcane transport system plays a critical role in the overall performance of Australia’s sugarcane industry. An inefficient sugarcane transport system interrupts the raw sugarcane harvesting process, delays the...The sugarcane transport system plays a critical role in the overall performance of Australia’s sugarcane industry. An inefficient sugarcane transport system interrupts the raw sugarcane harvesting process, delays the delivery of sugarcane to the mill, deteriorates the sugar quality, increases the usage of empty bins, and leads to the additional sugarcane production costs. Due to these negative effects, there is an urgent need for an efficient sugarcane transport schedule that should be developed by the rail schedulers. In this study, a multi-objective model using mixed integer programming (MIP) is developed to produce an industry-oriented scheduling optimiser for sugarcane rail transport system. The exact MIP solver (IBM ILOG-CPLEX) is applied to minimise the makespan and the total operating time as multi-objective functions. Moreover, the so-called Siding neighbourhood search (SNS) algorithm is developed and integrated with Sidings Satisfaction Priorities (SSP) and Rail Conflict Elimination (RCE) algorithms to solve the problem in a more efficient way. In implementation, the sugarcane transport system of Kalamia Sugar Mill that is a coastal locality about 1050 km northwest of Brisbane city is investigated as a real case study. Computational experiments indicate that high-quality solutions are obtainable in industry-scale applications.展开更多
Rail transport in most developing countries, is usually the least developed mode. For instance, in Nigeria the vibrant fortune of rail transport operations and development has been on decline since mid 1970s.The devel...Rail transport in most developing countries, is usually the least developed mode. For instance, in Nigeria the vibrant fortune of rail transport operations and development has been on decline since mid 1970s.The developmental gap in rail transport in Nigeria is responsible for a significant level of access denial to a safer, affordable and environmentally-friendly mode of transport, to the younger generation of Nigerians. Through a critique of past railways developmental projects and policies, this paper was able to identify the principal factors responsible for its intangible contributions to the socio-economic development of Nigeria. It further highlighted the role(s) politics of policies inconsistency and somersault plays, to the detriment of realization of a vibrant railway system in Nigeria. The findings revealed that discontinuity and incoherence in policy implementation by successful governments, policy reversal as well as uncoordinated national transport policy goal and objectives as clogs in the wheel of progress of railways development in Nigeria. In conclusion, the paper hinged the rapid development of the rail industry in Nigeria on institutional paradigm shift, whereby the rail authority will enjoy a reasonable level of autonomy in decision making, finance and investment in rail operations, infrastructure supply and technological advancement in Nigeria.展开更多
This article first talks about railways in general and ballast in particular. An inventory is then made on the modernization of the Senegalese ballast railways. In the second phase, an experimental work of characteriz...This article first talks about railways in general and ballast in particular. An inventory is then made on the modernization of the Senegalese ballast railways. In the second phase, an experimental work of characterization of basaltic aggregates of Diack (Locality of Ngoundiane, Thiès region, Senegal) is presented. The grain size studied is 25/50 mm as for any material studied for use as railway ballast. Experimental work presented consists of the characterization of the shape of an aggregate using the NF P 18-301 standard. The test consists of comparing the volume of the aggregate to that of an equivalent sphere with the largest diameter of the aggregate, by calculating the average volume coefficient. With a Representative Elementary Volume (REV) of 6 aggregates, the volume coefficient “C<sub><span style="font-family:Verdana;">v</span></sub><span style="font-family:Verdana;">” fluctuates between 0.27 and 0.49 with an average volume coefficient of 0.39 which is well above 0.15</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The grains studied are polyhedral and therefore have a high mechanical resistance.</span></span></span>展开更多
The high peak hour demand in Urban Rail Transport (URT) is usually met by supply side measures such as pushing more number of trains/cars in peak hour by the operator. This additional capacity generates more demand du...The high peak hour demand in Urban Rail Transport (URT) is usually met by supply side measures such as pushing more number of trains/cars in peak hour by the operator. This additional capacity generates more demand due to a positive elasticity of demand with respect to services. Delhi Metro Rail Corporation (DMRC), India has converted its fleet from 4 cars per train to 6 cars per train and finally to 8 cars per train on its Broad Gauge section. The ridership of the system has also witnessed double digit growth during this conversion period. The demand elasticity w.r.t services for the passengers of DMRC has been estimated as 0.512 on the basis of growth of demand and increase in capacity after adjusting for natural growth. So a 10% increase in supply results into 5% increase in capacity. A simple service elasticity model has been developed to estimate demand with increase in supply. The model has been applied to Line 2 (yellow line), the busiest line of DMRC, to estimate the demand for different level of services (trains/hour). The efficacy of supply side measures is limited by the design capacity of the system beyond which any increase in supply would require disproportionate investment. An optimum combination of supply and demand side measures would perhaps be the best way to address peak hour congestion in Urban Rail Transport.展开更多
Many developed countries in the world have adopted high technology to rebuild and improve the rail transportation industry actively. It has greatly increased the security and automation degree of rail transportation. ...Many developed countries in the world have adopted high technology to rebuild and improve the rail transportation industry actively. It has greatly increased the security and automation degree of rail transportation. Since “the ninth five year plan", the velocity and quality of rail transportation infrastructure construction have been improved quickly by applying high technology in China. However, there still exist many differences between China and the developed countries in the development of rail transportation. In this paper the author systematically introduced the application of high technology in rail transportation such as railway, metro, light railway, railway nearby su\| burb, maglev railway, etc. and also the development road to high technology industrialization in transportation field, on the basis of viewing the current development condition and the trend of rail transportation in the world and analyzing the development status and trend of rail transportation in China.展开更多
Rail systems are gradually becoming the most desirable form of transit infrastructure around the world, partly because they are becoming more environmentally friendly compared with airplanes and automobiles. This pape...Rail systems are gradually becoming the most desirable form of transit infrastructure around the world, partly because they are becoming more environmentally friendly compared with airplanes and automobiles. This paper examines the place of emerging countries in this move of implementing modern rail system that will eventually enhance the realization of a low-carbon society. Network model, transportation model and linear programming algorithms are used to model the present urban rail transport system in Nigeria, as an emerging country, in order to optimize it. Operational research methods, including simplex method and MODI, with the aids of computer software (excel solver and LIP solver) were adopted to solve the resulting models. The results showed that optimization of rail transport system will not only reduce carbon emission but also bring about economic development which is required for the eradication of prevalent poverty in these emerging countries.展开更多
In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and curren...In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and current phenomena have been frequently reported in electric motors,with electrical bearing failures making up a considerable percentage.The purpose of this review is to provide a comprehensive overview of facets relating to the electrical erosion of bearings in an electrical environment represented by railway vehicles.First,the origins of the phenomenon as well as typical bearing electrical failure modes are discussed.Next,we introduce the distinctive features of the electrical environment of railway traction motor bearings,including output voltages with high common-mode components and systems with complex grounding configurations.Then,we classify the fundamental mechanisms for generating bearing voltages/currents into four groups,and present their modeling processes,including equivalent circuit establishment and parameter determination methods.Furthermore,we summarize the strategies frequently used to protect bearings,and describe a typical solution to suppress electrical bearing failures in railway vehicles.Finally,we present a case example to illustrate a research procedure for systematic investigation of inverter-induced bearing currents in rail transportation.展开更多
As essential pillars of passenger mobility and freight transport,road and rail transportation have experienced a rapid increase over the past years.This trend indicates an increase in energy consumption,especially ele...As essential pillars of passenger mobility and freight transport,road and rail transportation have experienced a rapid increase over the past years.This trend indicates an increase in energy consumption,especially electricity,due to higher energy efficiency and less carbon emission,but it exacerbates the contradiction between the power supply and demand.Nowadays,for additional power sources,increased solar power generation has been widely installed in their own available spaces for road and rail transportation,which has attracted a great deal of attention.This paper reviews the current status of solar power generation and its integrated application in the transport sector.Then,the photovoltaic generation potential of road and rail transportation in China are evaluated.Finally,further developments and perspectives of solar energy-powered road and rail transportation are presented,which not only contributes to lower-carbon and green transportation,but also promotes the development of renewable power generation for energy transformation.It is confirmed that solar energy-powered road and rail transportation is a promising approach for sustainable transportation with more renewable energy and less carbon emission.展开更多
Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions a...Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions are being sought to transfer a large part of passengers and especially freight transport to(high-speed)rail,and efforts are moving towards electromobility,car-sharing,5G-connectivity,autonomous driving,MaaS(Mobility as a Service)-coordinated transport or hyperloop-type solutions.However,all these solutions have additional challenges and limitations.Solutions are not being searched where they really exist-in the mutual adaptation of road and rail vehicles and their deep cooperation.The ComplexTrans project shows that simply adapting the dimensions and functions of road and rail vehicles can eliminate(or at least significantly reduce)all the problems of existing land transport.The main features of the ComplexTrans system are sufficient parking spaces,reduction of urban and non-urban congestion,electric vehicles with unlimited range and cheaper than standard cars,cheaper and more accessible battery charging,“autonomous ride”,solving the overlap between passenger and freight rail transport and making it self-financing,transferring intercity freight transport to rail,replacing part of continental air transport and many others.The cost-effective and clustered individual transport and individualised public transport of the ComplexTrans system also bring very significant reductions in the risk of transmission of covid-19 and other contagious diseases during transport.展开更多
China has a vast land area and frequent interconnections between various regions.China's transportation industry is faced with tremendous pressure.This article combines China’s railway and highway transportation ...China has a vast land area and frequent interconnections between various regions.China's transportation industry is faced with tremendous pressure.This article combines China’s railway and highway transportation conditions to predict China’s economic development,uses stepwise regression to screen explanatory variables,and finally determines railway passenger turnover,road freight volume and passenger car ownership as the explanatory variables,and GDP as the dependent variable,and also analyzes China’s economic development by establish ing a multiple regression model.展开更多
[目的]通过总结上海城市轨道交通既有线运能提升改造项目的实施经验,为其提出有效的运能提升方法及具体案例。[方法]深入分析上海轨道交通既有线运能不足的主要原因及其影响因素;基于这些分析,提出运能提升的技术路线及5大核心策略;详...[目的]通过总结上海城市轨道交通既有线运能提升改造项目的实施经验,为其提出有效的运能提升方法及具体案例。[方法]深入分析上海轨道交通既有线运能不足的主要原因及其影响因素;基于这些分析,提出运能提升的技术路线及5大核心策略;详细介绍了上海轨道交通9号线实现1 min 50 s最小行车间隔、3号线与4号线增能改造、5号线从4节编组扩编至6节编组、6号线增能改造及增设复线等成功案例。[结果及结论]影响线路运能的主要因素包括车辆基地规模、区间通过能力、出入场能力,以及供电能力等。针对这些因素,确定了运能提升的技术路线,即从客流预测及客流特征分析入手,进行设施设备能力评估,设计行车交路方案,最终形成科学的改造方案。同时,提出了5大策略:运营管理优化、既有系统能力挖潜及改造、信号系统升级或土建局部改造、系统规模性改造及线网整体优化。展开更多
文摘Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria.However,while rail transport continues to enjoy relative importance in terms of investment,growth and contribution to the national economy in several countries,it has suffered and declined(in terms of modal share contribution which has led to decreased patronage)in Nigeria.However,there are new developments and investment on rail and some measures are being put in place to revive the Nigerian rail transport system.As these new developments and rehabilitations are going on,it will be imperative to know what the users/customers think as well,so that they are not left out because under normal circumstances,customers need transport services and not rail transport services.Therefore,if they were not satisfied with rail transport services they would simply turn to other modes of transport.As part of an on-going PhD research project,this paper focuses on the perceptions of Nigerian rail transport users/customers regarding the quality of rail services provided.Data was collected by the use of structured/semi-structured questionnaires,which were distributed,to the respondents.The study sample included 474 respondents between the age range of 20-70 out of which just 21(4.4%)have used rail transport;this low patronage figure is as a result of the long time neglect of the Nigerian rail transport system while 474(100%)of the correspondents use road transport daily which has led to an increasing pressure on road transport and infrastructures.Data was collected respectively from the following cities:Lagos,Warri,Ughelli and Benin.
文摘The sugarcane transport system plays a critical role in the overall performance of Australia’s sugarcane industry. An inefficient sugarcane transport system interrupts the raw sugarcane harvesting process, delays the delivery of sugarcane to the mill, deteriorates the sugar quality, increases the usage of empty bins, and leads to the additional sugarcane production costs. Due to these negative effects, there is an urgent need for an efficient sugarcane transport schedule that should be developed by the rail schedulers. In this study, a multi-objective model using mixed integer programming (MIP) is developed to produce an industry-oriented scheduling optimiser for sugarcane rail transport system. The exact MIP solver (IBM ILOG-CPLEX) is applied to minimise the makespan and the total operating time as multi-objective functions. Moreover, the so-called Siding neighbourhood search (SNS) algorithm is developed and integrated with Sidings Satisfaction Priorities (SSP) and Rail Conflict Elimination (RCE) algorithms to solve the problem in a more efficient way. In implementation, the sugarcane transport system of Kalamia Sugar Mill that is a coastal locality about 1050 km northwest of Brisbane city is investigated as a real case study. Computational experiments indicate that high-quality solutions are obtainable in industry-scale applications.
文摘Rail transport in most developing countries, is usually the least developed mode. For instance, in Nigeria the vibrant fortune of rail transport operations and development has been on decline since mid 1970s.The developmental gap in rail transport in Nigeria is responsible for a significant level of access denial to a safer, affordable and environmentally-friendly mode of transport, to the younger generation of Nigerians. Through a critique of past railways developmental projects and policies, this paper was able to identify the principal factors responsible for its intangible contributions to the socio-economic development of Nigeria. It further highlighted the role(s) politics of policies inconsistency and somersault plays, to the detriment of realization of a vibrant railway system in Nigeria. The findings revealed that discontinuity and incoherence in policy implementation by successful governments, policy reversal as well as uncoordinated national transport policy goal and objectives as clogs in the wheel of progress of railways development in Nigeria. In conclusion, the paper hinged the rapid development of the rail industry in Nigeria on institutional paradigm shift, whereby the rail authority will enjoy a reasonable level of autonomy in decision making, finance and investment in rail operations, infrastructure supply and technological advancement in Nigeria.
文摘This article first talks about railways in general and ballast in particular. An inventory is then made on the modernization of the Senegalese ballast railways. In the second phase, an experimental work of characterization of basaltic aggregates of Diack (Locality of Ngoundiane, Thiès region, Senegal) is presented. The grain size studied is 25/50 mm as for any material studied for use as railway ballast. Experimental work presented consists of the characterization of the shape of an aggregate using the NF P 18-301 standard. The test consists of comparing the volume of the aggregate to that of an equivalent sphere with the largest diameter of the aggregate, by calculating the average volume coefficient. With a Representative Elementary Volume (REV) of 6 aggregates, the volume coefficient “C<sub><span style="font-family:Verdana;">v</span></sub><span style="font-family:Verdana;">” fluctuates between 0.27 and 0.49 with an average volume coefficient of 0.39 which is well above 0.15</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The grains studied are polyhedral and therefore have a high mechanical resistance.</span></span></span>
文摘The high peak hour demand in Urban Rail Transport (URT) is usually met by supply side measures such as pushing more number of trains/cars in peak hour by the operator. This additional capacity generates more demand due to a positive elasticity of demand with respect to services. Delhi Metro Rail Corporation (DMRC), India has converted its fleet from 4 cars per train to 6 cars per train and finally to 8 cars per train on its Broad Gauge section. The ridership of the system has also witnessed double digit growth during this conversion period. The demand elasticity w.r.t services for the passengers of DMRC has been estimated as 0.512 on the basis of growth of demand and increase in capacity after adjusting for natural growth. So a 10% increase in supply results into 5% increase in capacity. A simple service elasticity model has been developed to estimate demand with increase in supply. The model has been applied to Line 2 (yellow line), the busiest line of DMRC, to estimate the demand for different level of services (trains/hour). The efficacy of supply side measures is limited by the design capacity of the system beyond which any increase in supply would require disproportionate investment. An optimum combination of supply and demand side measures would perhaps be the best way to address peak hour congestion in Urban Rail Transport.
文摘Many developed countries in the world have adopted high technology to rebuild and improve the rail transportation industry actively. It has greatly increased the security and automation degree of rail transportation. Since “the ninth five year plan", the velocity and quality of rail transportation infrastructure construction have been improved quickly by applying high technology in China. However, there still exist many differences between China and the developed countries in the development of rail transportation. In this paper the author systematically introduced the application of high technology in rail transportation such as railway, metro, light railway, railway nearby su\| burb, maglev railway, etc. and also the development road to high technology industrialization in transportation field, on the basis of viewing the current development condition and the trend of rail transportation in the world and analyzing the development status and trend of rail transportation in China.
文摘Rail systems are gradually becoming the most desirable form of transit infrastructure around the world, partly because they are becoming more environmentally friendly compared with airplanes and automobiles. This paper examines the place of emerging countries in this move of implementing modern rail system that will eventually enhance the realization of a low-carbon society. Network model, transportation model and linear programming algorithms are used to model the present urban rail transport system in Nigeria, as an emerging country, in order to optimize it. Operational research methods, including simplex method and MODI, with the aids of computer software (excel solver and LIP solver) were adopted to solve the resulting models. The results showed that optimization of rail transport system will not only reduce carbon emission but also bring about economic development which is required for the eradication of prevalent poverty in these emerging countries.
基金supported by the National Key R&D Program of China(No.2018YFB1201804)the National Natural Science Foundation of China(Nos.52293424,51827810,and 51977192).
文摘In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and current phenomena have been frequently reported in electric motors,with electrical bearing failures making up a considerable percentage.The purpose of this review is to provide a comprehensive overview of facets relating to the electrical erosion of bearings in an electrical environment represented by railway vehicles.First,the origins of the phenomenon as well as typical bearing electrical failure modes are discussed.Next,we introduce the distinctive features of the electrical environment of railway traction motor bearings,including output voltages with high common-mode components and systems with complex grounding configurations.Then,we classify the fundamental mechanisms for generating bearing voltages/currents into four groups,and present their modeling processes,including equivalent circuit establishment and parameter determination methods.Furthermore,we summarize the strategies frequently used to protect bearings,and describe a typical solution to suppress electrical bearing failures in railway vehicles.Finally,we present a case example to illustrate a research procedure for systematic investigation of inverter-induced bearing currents in rail transportation.
基金This work was supported in part by the National Natural Science Foundation of China(No.51807182).
文摘As essential pillars of passenger mobility and freight transport,road and rail transportation have experienced a rapid increase over the past years.This trend indicates an increase in energy consumption,especially electricity,due to higher energy efficiency and less carbon emission,but it exacerbates the contradiction between the power supply and demand.Nowadays,for additional power sources,increased solar power generation has been widely installed in their own available spaces for road and rail transportation,which has attracted a great deal of attention.This paper reviews the current status of solar power generation and its integrated application in the transport sector.Then,the photovoltaic generation potential of road and rail transportation in China are evaluated.Finally,further developments and perspectives of solar energy-powered road and rail transportation are presented,which not only contributes to lower-carbon and green transportation,but also promotes the development of renewable power generation for energy transformation.It is confirmed that solar energy-powered road and rail transportation is a promising approach for sustainable transportation with more renewable energy and less carbon emission.
基金This research is partly supported by project SGS-2019-001The 3-D visualisations were prepared by students of University of West Bohemia or by professional designers.
文摘Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions are being sought to transfer a large part of passengers and especially freight transport to(high-speed)rail,and efforts are moving towards electromobility,car-sharing,5G-connectivity,autonomous driving,MaaS(Mobility as a Service)-coordinated transport or hyperloop-type solutions.However,all these solutions have additional challenges and limitations.Solutions are not being searched where they really exist-in the mutual adaptation of road and rail vehicles and their deep cooperation.The ComplexTrans project shows that simply adapting the dimensions and functions of road and rail vehicles can eliminate(or at least significantly reduce)all the problems of existing land transport.The main features of the ComplexTrans system are sufficient parking spaces,reduction of urban and non-urban congestion,electric vehicles with unlimited range and cheaper than standard cars,cheaper and more accessible battery charging,“autonomous ride”,solving the overlap between passenger and freight rail transport and making it self-financing,transferring intercity freight transport to rail,replacing part of continental air transport and many others.The cost-effective and clustered individual transport and individualised public transport of the ComplexTrans system also bring very significant reductions in the risk of transmission of covid-19 and other contagious diseases during transport.
文摘China has a vast land area and frequent interconnections between various regions.China's transportation industry is faced with tremendous pressure.This article combines China’s railway and highway transportation conditions to predict China’s economic development,uses stepwise regression to screen explanatory variables,and finally determines railway passenger turnover,road freight volume and passenger car ownership as the explanatory variables,and GDP as the dependent variable,and also analyzes China’s economic development by establish ing a multiple regression model.
文摘[目的]通过总结上海城市轨道交通既有线运能提升改造项目的实施经验,为其提出有效的运能提升方法及具体案例。[方法]深入分析上海轨道交通既有线运能不足的主要原因及其影响因素;基于这些分析,提出运能提升的技术路线及5大核心策略;详细介绍了上海轨道交通9号线实现1 min 50 s最小行车间隔、3号线与4号线增能改造、5号线从4节编组扩编至6节编组、6号线增能改造及增设复线等成功案例。[结果及结论]影响线路运能的主要因素包括车辆基地规模、区间通过能力、出入场能力,以及供电能力等。针对这些因素,确定了运能提升的技术路线,即从客流预测及客流特征分析入手,进行设施设备能力评估,设计行车交路方案,最终形成科学的改造方案。同时,提出了5大策略:运营管理优化、既有系统能力挖潜及改造、信号系统升级或土建局部改造、系统规模性改造及线网整体优化。