Modelling of wheels and rail discontinuities in dynamic wheel-rail contact analysis

A classification of wheel-rail contact is given. Difference is made between modelling of a running wheel with continuous single-point-contact, as is common practice in wheel-rail contact analysis, and a wheel with transient double- or multi-point-contact, which may occur for rail irregularities with curvatures larger than that of the wheel circumference. It is shown that application of the first model for these irregularities will strongly underestimate the contact forces as it does not describe occurring mechanisms correctly. Further, it is shown that in principle it is not possible to describe the second type of contact fully correct with a lumped wheel model. Both wheel models are formulated mathematically for some basic contact cases. Afterwards, results are applied to a linear track model. Analytical closed-form solutions are found in the frequency domain for arbitrary type of contact and numerically transformed to the time domain. Finally, the necessity is shown to avoid situations where transient multiple-point-contact may occur (like rail joints) in practice.     

智能交通系统及其车辆自动控制技术

本文简要介绍了智能交通系统的概念、发展状况、基本内容和研究开发过程，进一步阐述了智能交通系统中的先进车辆控制技术。综述了汽车纵向控制、横向控制、自动驾驶及车列控制。最后，对我国如何发展智能交通系统和先进车辆自动控制技术进行了探讨。     

European freight transport and the environment: empirical applications and scenarios

Environmental issues have received a prominent place in transport policies of most European countries. The coordination of such policies however, is fraught with many difficulties. The increasing freight flows after the European integration are a source of concern, but have not yet led to straightforward and effective environmental strategies.The paper focuses on the Trans Alpine freight transport systems in the light of the future integration of single national transport systems into the European transport network. The environmental, social and institutional peculiarities of this ‘region’ have favoured—in the past—the development of strong nationally-oriented policies, partly in contrast with the goals promoted by the European Union. The present analysis aims to highlight opportunities, and limits inherent, in the implementation of various infrastructure projects oriented towards a drastic change of the Alpine transport systems structure. The Alpine countries, viz. Austria and Switzerland, play a central role in the promotion of environmental benign modes of transport of goods, with a clear focus on rail. The route choice and modal split of freight flows in Europe are taking place simultaneously. In this paper the results of European freight flow models (based on logit analysis and neural networks) will be presented. An important exercise is then to assess the consequences of various types of eco-taxes on road transport in Europe. In this context, several policy scenarios will be dealt with.     

船舶气囊下水工艺实践与发展前景

本文叙述船舶气囊下水新工艺在我国内河中、小型船厂近年来的实践，提出和总结气囊下水工艺有关计算方法和注意事项。鉴于气囊下水新工艺有其独特的优越性，并随着气囊制造质量和下水工艺不断完善提高，气囊下水新工艺必会有较好的发展前景，下水船舶重量期望可提高到2000t。     

街道设计理念下工程实践的若干思考

“完整街道”、“街道设计”等城市道路改造设计理念开始广泛应用于城市道路旧改等实际工程项目。然而，街道设计理念与传统的设计习惯、道路管理模式及使用者的接受程度，依然在现实应用以及工程实施上存在较大的分歧。以深圳市罗湖区道路设施品质提升工程和深圳市罗湖区精品示范路工程两个项目为工程背景，分别从宏观的街道空间改造和部分微观细节设计两个角度，分析项目实施过程中存在的难点和优化处置方案，为后续工程实践以及相关街道设计导则优化提供借鉴。     

An integrated assessment of alternative land-based passenger transport policies: A case study in Tenerife

Over recent decades, there have been numerous cases of land-based transport policies that have lacked clear and coherent strategies. This has not only hampered the resolution of issues like road congestion, but has also created new ones (e.g. strong social opposition to new train infrastructures). The absence of such strategies highlights the need for long-term transport policies with a wider vision of the issues, since land-based transport cannot be considered from just a technical perspective.The main objective of this article is to implement a participatory integrated approach to facilitate the understanding of land-based passenger transport governance issues on Tenerife, in the Canary Islands. Relevant policy issues and alternatives are identified by the stakeholders involved. The inclusion of stakeholders in the assessment process is crucial to frame transport governance issues appropriately and to define and assess plausible policy alternatives. This assessment process even included a final step of validation of the results by stakeholders to foster discussion among them about transport issues and policy alternatives.Finally, due to the obstructive role played by some stakeholders in influencing past transport policies, an analysis of possible coalitions among stakeholders is also discussed.     

The best of times and the worst of times: A new best–worst measure of attitudes toward public transport experiences

Attitudes play an important role in determining individual transit behaviour and the measurement of attitudes is relied on by public transit authorities’ world over. Given their role in behaviour and policy making, the accurate measurement of attitudes is of critical importance. Traditional satisfaction scales are prone to bias and on their own they are only a partial measure of attitudes. Given that satisfaction scales have been used to assist with large scale transport infrastructure investment decisions, to aid policy makers examining reactions to alternative policy changes and reform, and to measure the success of new initiatives, deriving robust satisfaction scales should be of critical importance. This paper introduces a dual version of best–worst scaling as an alternative measure of satisfaction. Best–worst scaling is free of the biases inherent in traditional response scales and is ideal for handling the comparative evaluation of large amount of attributes, particularly those which are inherently qualitative. The paper makes a further innovative contribution by proposing a model structure for the joint estimation of satisfaction and importance. Our model shows a better delineation between the attributes used to measure attitudes towards bus use and a more detailed understanding of the relationship between importance and satisfaction; enabling transport operators to better understand what counts most and assess their performance.     

浅析大型铁路客运站交通规划理念

以重庆北站北场交通规划为例,分析和判断了铁路客流对象、车站客流组织、旅客立体换乘、车站功能布局和车站管理模式5个方面的发展趋势；提出了现代铁路客运站在综合交通枢纽、站前集散广场、机动车进出通道、交通设施布局、客流组织方面的规划设计理念.     

沟埋式钢波纹管涵顶部垂直土压力计算模型研究

管涵周围土压力的分布规律对管涵结构的设计具有重要的参考价值,然而采用传统M-S理论计算管涵顶部垂直土压力存在一定的局限性。针对这一问题,以沟埋式管涵为研究对象,首先运用理论分析的方法对土体在沟槽摩擦作用下形成的小主应力拱展开了研究,并据此对矩形沟槽管涵的侧压力系数和顶部垂直土压力计算公式加以推导。然后以具体工程为例,对公式的合理性进行了探讨和分析,并对管涵的设计提出了一些合理性建议。     

对加快农村汽车客运站建设及运营管理的分析

农村汽车客运站是农村道路运输的重要公益性基础设施，是整个道路运输市场体系的重要组成部分。农村汽车客运站的建设对改善农民群众出行条件、提升乡镇公共服务水平、推动农村经济发展、服务“三农”、建设社会主义新农村具有重要意义。文章针对当前农村汽车客运站建设及运营管理存在的问题，提出整改思路。