An overview of bearing voltages and currents in rail transportation traction motors

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.

A Perspective on Solar Energy-powered Road and Rail Transportation in China

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.

ComplexTrans-Global Rail-Road Transportation System Economical and Clustered Individual and Individualised Public Transport also Prevents the Spread of Covid 19

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.

Analysis of the Relationship Between Railway and Highway Transportation and China's Economic Development

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.

An Analysis of Users’/Customers’Perceptions of the Nigerian Rail Transport Services

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.

A New Multi-Objective Model to Optimise Rail Transport Scheduler

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.

Factors Analysis of Affecting Loading and Reinforcing Scheme of Large Goods in Railway

Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a reasonable scheme will be affected by many factors. This paper presents the characteristic of the large goods, summarizes the process of designing a loading and reinforcing scheme of large good, then probes the factors of affecting the loading and reinforcing scheme and gives a detail analysis. It’s considered that those out-of-gauge and overweight degree of goods, center-of- gravity height of a loaded wagon, position of center-of-gravity of goods, type of wagon for using, reinforcement material and reinforcement method, transport expense and transport organization could affect a scheme in the aspects of safety, economy, rapidity and convenience. This conclusion will instruct and help to make a good scheme.

Politics of Rail Transport Development in Developing Countries： Case of Nigeria

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.

Experimental Characterization of Shape of an Aggregate by a Numerical Value—Application to Senegalese Basaltic Aggregates for Rail Transport

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 “Cv” fluctuates between 0.27 and 0.49 with an average volume coefficient of 0.39 which is well above 0.15. The grains studied are polyhedral and therefore have a high mechanical resistance.

Demand Elasticity of Capacity Offered for Urban Rail Transport

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.

Research and Exploration on Innovation and Entrepreneurship Practice Education System for Railway Transportation Specialists

With the background of concept of rail transit major engineering,guided by industry demand,and based on the cultivation of practical abilities for outstanding engineering and technology talents in rail transit characteristic majors,we are committed to creating a national strategic innovation and entrepreneurship practical education system for rail transit characteristic professionals,continu-ously improving the practical teaching mode.We will carry out the construction of a“matrix style”practical teaching system that integrates the four modernizations,the construction of a virtual simulation practical teaching platform that integrates expertise and innovation,and open sharing,as well as the reform and explo-ration of the entire chain of integrated practical education.The scheme focuses on improving students’ability to solve complex engineering problems and their abil-ity to apply composite knowledge and innovate and start businesses,cultivating a large number of outstanding rail transit engineering talents with solid professional foundations,outstanding practical abilities,and innovative and entrepreneurial qualities.

Critical evaluation of transit policies in Lima,Peru;resilience of rail rapid transit(Metro)in a developing country

This paper evaluates rail transit within the context of the transit policies implemented in Lima,Peru.First it reviews the implementation of rapid transit,and bus reform.Secondly,it evaluates the outcomes of such policies by using Total Factor Productivity for policy effectiveness,Data Envelopment Analysis for rapid transit performance,and Generalized Cost of Travel for improvements.This paper finds that implementation failed in enforcing key requirements for rail transit regarding penetration of CBD and short transfers to bus transit;and that the basic assumptions of bus reform did not hold regarding bus oversupply,bus congestion or bus pollution.This paper also finds that outcomes of policies failed dramatically in achieving the planning goals;however,rail transit(Metro)shows high level of resilience in serving large ridership at high speed.On the other hand,bus reform was associated with a disproportionate increase of motorization,well over the effect of income growth or car attractiveness,and more related to the excessive reduction of bus transit capacity ill-advised from unproved bus reform assumptions.This paper recommends expanding rail rapid transit due to its intensive use of green renewable energy and its potential of demand growth if combined with modern Intelligent Transportation services,but this opportunity can be wasted without the proposed policy constraint to achieve lower Generalized Cost of Travel at any governmental intervention for bus reform,instead of just reducing bus transit capacity as implemented.Finally,this paper recommends government to government contracts to build rail transit and to enforce proper planning.

Advanced Strategies to Mobilize Crop Residue to Replace Coal in India

Various published data show the amount of crop residue available annually in India may range from a low of 90 to a high of 180 million tonnes. Different types of crop residue are collected from farmers depending on the geography and crop pattern for instance, in north India rice straw and cotton stalks are collected while in central India soya husk and sugarcane tops are collected. Baling and transporting straw from the field, though appear to be an option for safe disposal, will be feasible only when alternate, effective and economically viable usage methods are identified and facilities and infrastructure for ex-situ management methods are created. One immediate short term use of the residue is to replace 5% - 7% of the 670 million tonnes of coal India currently consumes to generate power. The farmers will benefit from the sale of their excess crop residue. The scheme will reduce pollution due to residue burning practices. Replacing coal will cut the GHG emissions. The challenge is to mobilize the crop residue collection and timely delivery to power plants. The data and calculations in this monogram show that it is economical for the farmer to remove the crop residue from the field quickly by using modern balers, to pelletize the biomass in small-scale distributed pellet plants, to store pellets in the modern steel bins and finally to deliver the pellets to coal plants by using rail transport. The delivered cost is estimated at around Rp 6.78/kg. The Government of India encourages the power plants to pay at least Rp 10/kg for the delivered biomass in the form of pellets. The current monogram analyzes the organization of an efficient supply chain in the State of Haryana India to ensure a sustainable modern enterprise.

Development of 8-inch Key Processes for Insulated-Gate Bipolar Transistor

Based on the construction of the 8-inch fabricat ion line, advanced process technology of 8-inch wafer, as well as the fourth-generation high-voltage double-diffused metal-oxide semiconductor(DMOS+) insulated-gate bipolar transistor(IGBT) technology and the fifth-generation trench gate IGBT technology, have been developed, realizing a great-leap forward technological development for the manufacturing of high-voltage IGBT from 6-inch to 8-inch. The 1600 A/1.7 kV and 1500 A/3.3 kV IGBT modules have been successfully fabricated, qualified, and applied in rail transportation traction system.

Research on train integrated positioning based on grey neural network

Train positioning is the key to ensure the transportation and efficient operation of the railway.Due to the low accuracy and the poor real-time of the train positioning,a train positioning system based on global navigation satellite system/inertial measurement unit/odometer(GNSS/IMU/ODO)combination framework and a train integrated positioning method based on grey neural network are put forward.A data updating method based on the established grey prediction model of train positioning is put forward,which uses the accumulation and summary of the grey theory for the rough prediction of the data.The purpose of the method is to reduce the noise of the original data.Moreover,the radial basis function(RBF)neural network is introduced to correct residual sequence of the grey prediction model.Compared with the single model calibration,this method can make full use of the advantages of each model,thus getting a high positioning accuracy in the case of small samples and poor information.Experiments show that the method has good real-time performance and high accuracy,and has certain application value.

Rail Transport in Urban China ──A Hard Process

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Dust collector localization in trouble of moving freight car detection system

For a long time,trouble detection and maintenance of freight cars have been completed manually by inspectors.To realize the transition from manual to computer-based detection and maintenance,we focus on dust collector localization under complex conditions in the trouble of moving freight car detection system.Using mid-level features which are also named flexible edge arrangement(FEA) features,we first build the edge-based 2D model of the dust collectors,and then match target objects by a weighted Hausdorff distance method.The difference is that the constructed weighting function is generated by the FEA features other than specified subjectively,which can truly reflect the most basic property regions of the 3D object.Experimental results indicate that the proposed algorithm has better robustness to variable lighting,different viewing angle,and complex texture,and it shows a stronger adaptive performance.The localization correct rate of the target object is over 90%,which completely meets the need of practical applications.

A review of electrical signal-based train transmission machinery diagnosis technology

Transmission machinery is widely used in railway vehicles and is an important component in driving the operation of trains.Such transmission components are prone to faults under long exposure to harsh environments and complex working conditions.This affects normal operation and order,and thus it is important to ensure their safe and reliable operation.Electrical signal-based diagnosis technology has advantages of easy signal acquisition,with no need to install additional sensors,nor embedded monitoring of the object components.It has gradually become a research hotspot in the field of rail transportation diagnosis.This paper describes the fault modes of transmission machinery,takes the electrical signal-based diagnosis method as the entry point,collates and compares the existing diagnosis methods and research results in this field.It analyses their advantages and disadvantages,and finally puts forward problems for current and future research and development.