重庆市国省干线公路灾害分析及防治措施

基于对重庆市国省干线公路灾害特性、类型、空间分布、原因机理进行研究,得出重庆市国省干线公路灾害发育,并且具有十分明显的分区发育特征的结论,分析了灾害发生的诱因,提出了充分重视地质勘查工作,合理规划和控制人类工程活动,严格控制工程质量,强化灾害分布预测,改进灾害时间预报的防治措施.     

轻型高速船用齿轮箱发展现状研究

轻型高速船用齿轮箱的发展对于我国船舶工业的发展起着重要作用。本文以造船完工量及游艇市场未来产业规模预测为数据基础,分析发展轻型高速船用齿轮箱的重要性。文章通过研究国内外轻型高速齿轮箱发展现状,总结其发展趋势。分析我国轻型高速船用齿轮箱发展中主要问题,并提出相应的措施,为我国在轻型高速齿轮箱发展提供研究基础。     

长江三角洲城际轨道交通的发展

长江三角洲地区经济发达,人员流动频繁,尽管其交通网络比较发达,但仍然与经济的快速增长不适应。因此,迫切需要加快建设以开行高密度公交化旅客列车为特征的新型城际轨道交通,从而建立现代化的综合交通体系,发挥区位优势,建立资源节约型、环境友好型社会。要坚持与区域总体规划密切配合、合理选择线网等原则,遵循长江三角洲城际轨道交通线网规划的发展目标,加快建设步伐,构建长江三角洲地区综合交通运输体系。     

Breakthrough innovations in intermodal freight transport

Breakthrough innovations, whether technological, organizational or both, are a necessity if the market share of intermodal freight transport is to expand. The main growth potential lies in the markets for flows over short distances, for perishable and high-value commodities, for small consignments, and for flows that demand speed, reliability and flexibility. It will take radical innovations to produce a breakthrough in the modal split and allow these new markets to be conquered. This special issue is based on papers presented at an international conference on freight transport automation and multimodality, held in Delft in May 2002, that are illustrative of the direction of breakthrough research and development (R&D) aimed at increasing the market share for intermodal transport.     

Discussions on rail in urban areas and rail history

This paper includes discussions on rail in urban areas and railway history. More specifically commonly used terms and definitions for rail services, policy and practice in urban areas are discussed followed by an overview of railway developments around the world.     

Use of combinatorial auctions in the railway industry: Can the “invisible hand” draw the railway timetable?

Rail capacity is currently administratively allocated in Europe, whereas the economic literature has often contemplated the opportunity of introducing market mechanisms, auctions in particular, into this industry. This article tries to fill the gap between practice and theory. It first describes the properties of rail capacity (rigidity and non-homogeneity) and shows that because of its very nature, this capacity must be allocated through combinatorial auctions. As identified by the economic literature, using combinatorial auctions introduces a lot of complexity (winner determination and information burden) into the allocation process. To deal with this complexity, some form of centralized planning is necessary to design the right market mechanisms and to allocate capacity. This could have strong consequences on the current deregulation process.     

RS20型交换机的配置方法

对RS20交换机的配置进行探索研究具有很强的实用性,重点介绍了RS20交换机在轨道交通无线通信系统中的应用,通过不断的实践摸索,初步掌握了一套快速配置RS20交换机的方法,并对这种配置方法进行了探讨.     

Nonlinear three-dimensional wagon-track model for the investigation of rail corrugation initiation on curved track

A nonlinear wagon-track model on curved track has been developed to characterize rail corrugation formation due to self-excitation of the wheel-rail stick-slip process. In this model, wagon movements were described using up to 78 degrees of freedom (DOFs) to model a three-piece freight bogie. Innovatively, the wheelset movements are described using nine DOFs, including torsional and bending modes about the longitudinal and vertical directions. The track modelling is considered as a one-layer structure (two rail beams on discrete spring and damper elements). The wheel sliding after creepage saturation is considered in the wheel-rail interface modelling. Simulation of a case study shows that the frequencies of the wheel stick-slip process are composed of the basic frequency, which might come from the combined effect of sleeper-passing frequency and one-third of the combined torsional and bending frequency of the wheelset, and the double and triple basic frequencies, which form the wavelengths of rail corrugation at different situations.     

辗压混凝土机械化施工的体会

本文以交通部第二公路工程局1990年在安徽省312国道进行辗压混凝土施工中,如何解决诸如辗压混凝土路面结构、路面平整度、摊铺厚度、混合料级配、离析的影响以及自卸车倒料、压实、运输与摊铺等问题,并参考有关资料,进一步探讨了辗压混凝土施工工艺及施工机械的合理配套.     

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.