Rails_00009

1IntroductionSimon IwnickiCONTENTSI.Aims (1)II.Structure of the Handbook (2)I.AIMSThe principal aim of this handbook is to present a detailed introduction to the main issues influencing the dynamic behaviour of railway vehicles and a summary of the history and state of the art of the analytical and computer tools and techniques that are used in thisfield around the world. The level of technical detail is intended to be sufficient to allow analysis of common practical situations but references are made to other published material for those who need more detail in specific areas.The main readership will be engineers working in the railway industry worldwide and researchers working on issues connected with railway vehicle behaviour,but it should also prove useful to those wishing to gain a basic knowledge of topics outside their specialist technical area.Although in the very earliest days of the railways(as described in Chapter2)an individual was responsible for all aspects of the design of a railway,for most of the historical period of railways the vehicles(or rolling stock)have been under the control of mechanical engineers whereas the track has been seen as the domain of civil engineers.The focus of this book being on the vehicles would tend to put itfirmly in the mechanical domain,but in fact,in recent years this rather artificial divide has been lessened as engineers have been forced to consider the railway as a system with the wheel–rail interface at its centre.Increasing use of electrical and electronic components to power, control(or in some cases replace)the basic mechanical components has brought electrical, electronic,mechatronic and control engineers into the teams.The development of equations that represent the complex interactions between a vehicle and the track and of computers able to provide fast solutions to these equations has relied upon the expertise of software engineers and even mathematicians.The topics covered in this handbook are the main areas which impact on the dynamic behaviour of railway vehicles.These include the analysis of the wheel–rail interface,suspension and suspension component design,simulation and testing of electrical and mechanical systems, interaction with the surrounding infrastructure,and noise generation.Some related areas,such as aerodynamics or crashworthiness,are not covered as they tend to use different techniques and tools and have been extensively developed for road or air transport and are reported on elsewhere.The handbook is international in scope and draws examples from around the world,but several chapters have a more specific focus where a particular local limitation or need has led to the development of new techniques or tools.For instance,the chapter on longitudinal dynamics mainly uses Australian examples as the issues related to longitudinal dynamics cause most problems in heavy haul lines such as those in Australia where very long trains are used to transport bulk freight with extremely high axle loads,sometimes on narrow gauge track.Similarly,the issue of structure1gauging largely uses the U.K.as a case study,because here the historic lines through dense population centres have resulted in a very restricted loading gauge.The desire to run high-speed trains in this situation has led to the use of highly developed techniques to permit full advantage of the loading gauge to be taken.The issue of standards has been a tricky one due to the vast number of different organisations who set and control railway standards.It has not been possible to provide comprehensive guidance in this area but typical examples of the application of standards have been brought into the handbook where appropriate.For example,AAR Chapter XI standards for derailment in the U.S.and UIC518for limits on wheel–rail forces in the E.U.are presented.It should be stressed that these are intended only as illustrative examples of how the results of vehicle dynamic analyses can be used,and those with responsibility for safety should check carefully what the relevant current standards are for their work.II.STRUCTURE OF THE HANDBOOKThe history of the field is presented by Alan Wickens in Chapter 2,from the earliest thoughts of George Stephenson about the dynamic behaviour of a wheelset through the development of theoretical principles to the application of modern computing techniques.Professor Wickens was one of the pioneers of these methods and,as director of research at British Rail Research,played a key role in the practical application of vehicle dynamics knowledge to high-speed freight and passenger vehicles.In Chapter 3,Anna Orlova and Yuri Boronenko outline and explain the basic structure of the railway vehicle and the different types of running gear that are commonly used.Each of the relevant components is described and the advantages and disadvantages of the different types explained.The key area of any study of railway vehicle behaviour is the contact between the wheels and the rails.All the forces that support and guide the vehicle pass through this small contact patch,and an understanding of the nature of these forces is vital to any analysis of the general vehicle behaviour.The equations that govern these forces are developed by Hugues Chollet and Jean-Bernard Ayasse in Chapter 4.They include an analysis of the normal contact that governs the size and shape of the contact patch and the stresses in the wheel and rail and also the tangential problem where slippage or creep in the contact patch produces the creep forces which accelerate,brake,and guide the vehicle.The specific area of tribology applied to the wheel–rail contact is explained by Ulf Olofson and Roger Lewis in Chapter 5.The science of tribology is not a new one but has only recently been linked to vehicle dynamics to allow effective prediction of wheel and rail wear,and examples of this from the Stockholm local railway network are presented.Although the main focus of railway vehicle dynamics is traditionally on the vehicle,the track is a key part of the system and in Chapter 6Tore Dahlberg clearly explains the way that track dynamics can be understood.The contribution of each of the main components that make up the track to its overall dynamic behaviour is also presented.Chapter 7covers the unique railway problem of gauging,where the movement of a railway vehicle means that it sweeps through a space that is larger than it would occupy if it moved in a perfectly straight or curved path.Precise knowledge of this space or envelope is essential to avoid vehicles hitting parts of the surrounding infrastructure or each other.David M.Johnson has developed computer techniques that allow the gauging process to be carried out to permit vehicle designers and operators to ensure safety at the same time as maximising vehicle size and speed,and in this chapter he explains these philosophies and techniques.Of fundamental concern to all railway engineers is the avoidance of derailment and its potentially catastrophic consequences.Huimin Wu and Nicholas Wilson start Chapter 8with some statistics from the U.S.that show the main causes of derailment.They go on to summarise the limits Handbook of Railway Vehicle Dynamics 2Introduction3 that have been set by standards to try to prevent these occurrences,and cover the special case of independently rotating wheels and several possible preventative measures that can be taken.Longitudinal train dynamics are covered by Colin Cole in Chapter9.This is an aspect of vehicle dynamics that is sometimes ignored,but it becomes of major importance in heavy haul railways where very long and heavy trains lead to extremely high coupling forces between vehicles. This chapter also covers rolling resistance and braking systems.Chapter10deals with noise and vibration problems,which have become of greater concern in recent years.David Thompson and Chris Jones explain the key issues including rolling noise caused by rail surface roughness,impact noise,and curve squeal.They outline the basic theory required for a study in this area and also show how computer tools can be used to reduce the problem of noise. The effect of vibrations on human comfort is also discussed and the influence of vehicle design considered.In Chapter11,R.M.Goodall and T.X.Mei summarise the possible ways in which active suspensions can allow vehicle designers to provide advantages that are not possible with passive suspensions.The basic concepts from tilting bodies to active secondary and primary suspension components are explained in detail and with examples.Recent tests on a prototype actively controlled bogie are presented and limitations of the current actuators and sensors are explored before conclusions are drawn about the technology that will be seen in future vehicles.Computer tools are now widely used in vehicle dynamics and some specialist software packages allow all aspects of vehicle–track interaction to be simulated.Oldrich Polach,Mats Berg, and Simon Iwnicki have joined forces in Chapter12to explain the historical development and state of the art of the methods that can be used to set up models of railway vehicles and to predict their behaviour as they run on typical track or over specific irregularities or defects.Material in previous chapters is drawn upon to inform the models of suspension elements and wheel–rail contact,and the types of analysis that are typically carried out are described.Typical simulation tasks are presented from the viewpoint of a vehicle designer attempting to optimise suspension performance.Chapter13takes these principles into thefield and describes the main test procedures that can be carried out during the design or modification of a vehicle,or as part of an acceptance process to demonstrate safe operation.Julian Stow and Evert Andersson outline the range of transducers available to the test engineer and the ways that these can be most effectively used to obtain valid and useful data.The necessaryfiltering,corrections,and compensations that are normally made are explained,and data acquisition system requirements are covered.The chapter includes examples of the most commonly carried out laboratory andfield tests.An alternative tofield testing is to use a roller rig,on which,a vehicle can be run in relative safety with conditions being varied in a controlled manner and instrumentation can be easily installed.Weihua Zhang and his colleagues at Southwest Jiaotong University in China operate what is probably the most important roller rig in the world today and they outline the characteristics of this and other roller rigs and the ways in which they are used.Chapter14also reviews the history of roller rigs,giving summaries of the key details of examples of the main types.Chapter15extends the theme to scale testing,which has been used effectively for research into wheel–rail contact.In this chapter P.D.Allen describes the possible scaling philosophies that can be used and how these have been applied to scale roller rigs.In compiling this handbook I have been fortunate in being able to bring together some of the leading experts in each of the areas that make up thefield of railway vehicle dynamics.I and my coauthors hope that this handbook,together with its companion volume,Road and Off-Road Vehicle Dynamics,will be a valuable introduction for newcomers and a useful reference text for those working in thefield.Simon IwnickiManchester。

puts"The ID of this order is#{an_order.id}"new()构造函数会在内存中新建一个Order对象，我们必须记住在将来的某个时候将其存入数据库。

ActiveRecord提供了一个更为便利的create()方法，可以同时完成“实例化模型对象”和“将模型对象存入数据库”的操作。

e1/ar/new_examples.rban_order=Order.create(:name=>"Dave Thomas",:email=>"dave@",:address=>"123Main St",:pay_type=>"check")可以向create()传入一个hash数组作为参数，这样就会在数据库中创建多条记录，并返回对应模型对象的数组。

e1/ar/new_examples.rborders=Order.create([{:name=>"Dave Thomas",:email=>"dave@",:address=>"123Main St",:pay_type=>"check"},{:name=>"Andy Hunt",:email=>"andy@",:address=>"456Gentle Drive",:pay_type=>"po"}])rnew()和create()方法接受hash作为参数的真正原因在于：这样就可以直接拿表单数据来构造模型对象。

order=Order.new(params[:order])读取现有记录Reading Existing Rows要从数据库读取数据时，你必须首先说明自己对哪些数据感兴趣——你给ActiveRecord提供某些查询条件，它就会返回给你符合这些条件的对象。

Unit1Railway TransportationWarming UpTask11)C2)A3)B4)DTask21)loading2)boarding3)passenger stations4)freight stations 5)station buildings6)platforms7)mining sites8)portsIntensive Reading ATask11)shunting2)destination3)coordinate4)interlink5)wheeled6)calculate7)core8)accomplish Task21)C2)A3)C4)B5)BTask31)passenger service,riding rate,freight transportation,train operationrailway operation2)form filling,train loading,expense calculating,flow controlling,cargo consigningfreight transportation at the departure station3)cargo re-consignment,handover inspection,passenger service,cargo rearrangement, transfer arrangementfreight transportation at stopovers4)planning,flow controlling,shunting,good delivering,operation diagram drawingtrain operationTask41)Railway transportation is a means of transportation that transfers passengers and goods on wheeled vehicles running on rails.2)The basic task of railway passenger service is satisfying passengers’travel demand, providing them with a safe journey during which they won’t have to worry aboutanything.3)To smoothly transport the cargo to its destination,the working procedures of each station on the way should be interlinked.4)Train operation is the core part of railway transportation.5)The correct operation of passenger service,freight transportation,and train operation is essential for the safety and success of railway transportation.Task5(open-ended)课文翻译铁路运输——概述铁路运输是一种通过铁轨上运行的轮式车辆运送旅客和货物的运输方式。

redmine安装使用一、安装redmine安装方法很多，下面介绍一种简单的安装方案:1.下载集成安装包，下载地址/stack/redmine2.安装包下载后，点击运行，安装步骤很简单，基本上一路执行下一步就可以，有几个地方需要注意：语言选择最好选择英文（项目运行后可以选择中文显示）；创建密码的时候记住密码，这个密码是你数据库初始化时候admin账户的初始密码和登录数据库时候root账户的密码。

3.安装完成后，打开操作界面，如下图选择“Manager Servers”选项卡，如下图所有服务正常启动，则安装成功，如果没有启动则安装失败。

失败原因可能是端口占用、服务名称占用等原因，需要重新定义安装。

注：一件安装包内容如下：apache、redmine、php、ruby、mysql、phpadmin、svn。

二、集成插件使用bitnami-redmine一键安装的redmine项目集成普通插件十分简单。

1.首先需要到官网上下载支持所安装redmine版本的插件;2.将下载来的压缩包解压至%bitnami%/redmine-x.x.x-x/apps/redmine/htdocs/plugins目录下面。

3.将解压出来的文件夹名称由xxxxx-master改为xxxxx;4.打开“开始”—》“所有程序”—》“Bitnami Redmine Stack”—》使用“product fullname”,打开命令端。

5.cd命令切换到%bitnami%/redmine-x.x.x-x/apps/redmine/htdocs/plugins目录下面6.bundle install，安装集成插件需要的工具7.rake redmine:plugins:migrate RAILS_ENV=production,开始集成插件。

8.重启服务，再进如redmine，修改相关配置即可。

三、svn使用bitnami redmine意见安装默认启用svn服务，可以在本地新建svn仓库服务，也可以使用其他的svn仓库。