Exact Equations for Tractrix Curves Associated with Vehicle Offtracking

Vehicle offtracking behavior at low speeds is closely approximated by a geometric entity called a tractrix. This paper presents differential equations for generalized coordinates of a planar multibody vehicle model based on tractrix behavior. The equations are exact, can be used with any type of input path, are valid for forward and backward movements, and are much simpler than previously published formulations used to compute transient offtracking. The differential equations can be integrated using conventional numerical integration algorithms to obtain plots of the low-speed tracking performance of articulated vehicles. The equations were formulated symbolically by a computer program used to analyze the kinematic and dynamic behavior of multibody systems. Example numerical results are plotted.     

深化改革促进发展努力强化新体制新布局下的物资管理

回顾上海铁路局物资处2005年物资管理体制改革的实践及效果,并对2006年全局物资重点工作进行了安排.     

计量技术机构技术管理工作的发展方向

计量是融法制管理和专业技术于一体的工作，铁路计量同时又要求我们将管理统一于铁路运输管理体系之中。由于计量、安全检测设备是现代化的运输安全的重要保障基础，而这些设备得以正常发挥作用的基础是量值准确可靠。因此，保证这些设备量值准确性的量值溯源及设备状态监控、核查活动等的技术管理体系构成了运输安全管理体系和运输设备技术管理体系的重要组成部分，这是铁路计量的根本。随着铁路生产力布局结构的调整以及《计量法》的修订，对铁路局计量技术机构的技术管理工作来讲，是一个前所未有的机遇，同时也面临着严峻的考验，如何发挥自身的优势和作用，从长远看，技术机构朝着什么方向发展，如何处理自身建设问题等等，是摆在铁路计量工作者面前的重要课题。     

阿尔斯通开发的PRIMA 3U15型电力机车

阿尔斯通公司运输部开发了PRIMATM机车系列,其类型满足了运营部门提出的模块化和系列化要求.投放欧洲市场的PRIMA型电力机车既满足了通用性要求,又有助于与公路的经济竞争取得成效.为此,阿尔斯通公司继法国双流制机车后又开发了一种三流制机车,该型机车可用于法国、德国和瑞士之间的跨境运输.文章介绍PRIMATM系列的开发过程以及得到法国国家铁路的订单.详细叙述了PRIMA 3U15型三流制机车,重点是PRIMA电力机车的维修、可靠性和可用性.     

测定球面多点坐标计算球面参数的方法

无协作目标电子全站仪无需安置棱镜和反射片作为反射目标而能测定待定点的空间位置。采用无协作目标电子全站仪这一特性,可以方便地测定球面上多于4个点的三维坐标。以球心坐标和半径为未知数列出误差方程式,平差计算球心坐标和半径,并评定球心点位精度,实例证明该方法是可行和可靠的。     

Development and Deployment of Public Transport Policy and Planning in Taiwan

Over the past decade, the escalating roadway congestion and environmental deterioration due to heavy use of private vehicles have provoked the Taiwan government to realize the importance of public transport systems. Under the “carrot-and-stick” rationales, the government has formulated public transport policies and exercised a series of related initiatives by providing sufficient and higher quality of public transport services so as to attract more private vehicle users. In this paper, the planning philosophy and policy formulation of Taiwan’s public transport development are highlighted. The most important initiatives, including the Five-year Enhancement of Mass Transportation Program and the upgrading public transport schemes in the National Development Plan are examined. Based on previous experience and lessons, we point out the most challenging issues that the government will encounter. Suggestions for the future of public transport planning are also addressed.     

因地制宜,综合施治,务实解决街坊小区积水顽症

上海市杨浦区某些街坊小区一遇暴雨即产生严重的积水问题。通过调查研究，找出病症，提出改造方案．有效地解决了小区的积水顽症。本文结合实际，总结了若干综合技术措施和行政管理、协调手段。     

羽肠粉制取氨基酸的研究

在１００℃，６ｍｏｌ／Ｌ的硫酸作用下，含硬质粗蛋白很高的羽肠粉经１０ｈ水解可制得氨基酸态氮含量为５．２ｍｇ／ｍＬ的氨基酸。其水解液 的酸可用氧化钙中和至微酸性。过滤后的滤液经稀释做为农作物叶面喷施的有机液体肥，而剩余的滤渣亦可做缺硫土壤用的固体肥料。     

Analysis of Driver's Decelerating Strategy in a Car-following Situation

This report describes a decelerating driver-model expressed by driving mode transition in car-following situations. The assumptions for constructing the model are that decelerating strategy of a driver is classified into several simple driving modes and that a driver changs his driving modes based on his perceptible characteristics and experiential rules. Deceleration action is divided into three states; following, standing and braking, which are applied to the model. The model has two paths for driver's decelerating action, one of which is selected by the driver based on the perceptible characteristics and experiential rules. The suitability of the model has been experimentally verified.     

Multiphysic modelling of railway vehicles equipped with pneumatic suspensions

This article presents a multidisciplinary approach of railway pneumatic suspension modelling: both multibody and pneumatic aspects are taken into account. The work aims at obtaining a realistic model of the secondary suspension and coupling it with a multibody model of a train. Various components of the pneumatic circuit such as bellows, tanks, pipes and valves are taken into account. The article focuses on the bellow-pipe-tank subsystem for which several modelling approaches are presented and compared. Differences between differential and algebraic models are highlighted, and an application-dependent choice between them is suggested. A complete model of the pneumatic circuit is then obtained and coupled with a multibody model of the train. As a result, the behaviour of a suburban train equipped with a pneumatic secondary suspension is analysed, in particular undesired oscillating motions which affect the comfort. Topological modifications and improvements of the suspension are also investigated and discussed.