Influence of wheel and rail profile shape on the initiation of rolling contact fatigue cracks at high axle loads

The influence of wheel and rail profile shape features on the initiation of rolling contact fatigue (RCF) cracks is evaluated based on the results of multi-body vehicle dynamics simulations. The damage index and surface fatigue index are used as two damage parameters to assess the influence of the different features. The damage parameters showed good agreement to one another and to in-field observations. The wheel and rail profile shape features showed a correlation to the predicted RCF damage. The RCF damage proved to be most sensitive to the position of hollow wear and thus bogie tracking. RCF initiation and crack growth can be reduced by eliminating unwanted shape features through maintenance and design and by improving bogie tracking.     

IEC列车通信网络

国际电工委员会（ＩＥＣ）和国际铁路联盟（ＵＩＣ）为铁路车辆之间和车辆内互相联接的可编程设备制定了一项标准——《列车通信网络》（ＴＣＮ），其目的是有利于铁路运用部门、装配厂和设备供应商实现世界范围的车辆间的相互操作和插入式设备的联接。文章介绍了ＴＣＮ的体系结构，包括绞线式列车总线（ＷＴＢ）和多功能车辆总线（ＭＶＢ）的功能、技术参数、公共协议及网络管理，并对ＴＣＮ原型的开发、试验验证情况和标准草案工作进程作了简要的说明。     

Multi-impact optimization to reduce aviation noise and emissions

This paper describes a multi-indicator assessment and minimization problem focused on aviation “Community” noise. The model explores a combined noise and emission objective for airfreight movements at Luxembourg’s Findel Airport. Community noise is evaluated via four population impact indicators emissions are tabulated from in-flight segments in the proximity of the airport and from the contribution of taxiing. A set of scenarios based on trajectory, aircraft scheduling, fleet composition, operational procedures are implemented in software. An integer programming methodology is used to search for minimal environmental impact. An on/off switch allows for an evaluation of each indicator in the objective. Different impacts on the population are explored in a case study involving the Cargolux Airlines International S.A.     

休闲交通：公共交通公司的发展良机

瑞士的休闲交通量已达到650亿乘客／km，这意味着瑞士交通里程中有60％是属 于休闲交通范围内的。所以，未来的公共交通需要对这一巨大的潜能倾注更多的注意。 　　公共交通公司在它们的主要市场 上班族和长期车票使用者 的交通中正面临着扩大经 营的极限。虽然采取适当的调整措施可以增加一定程度的班次，拓宽一些供需渠道，但要实现运输 量的飞跃，只有在特殊情况下才有可能（例如当一个地区的服务业或经济水平迅猛发展时）。 除了山区旅游线路以外，很显然，交通公司的服务重点主要是那些长期乘车的顾客。而与此形成鲜明对 照的，是休闲交通可能提供的其它服务项目，但至少在目前，人们对休闲交通的充分开发还没有足 够的认识。 　　休闲交通的特征 　　休闲交通与日常交通在各方面都有很大的区别。在闲暇时，人们有了更多选择的自由。 人们在闲暇时间里是否有外出的希望，想去干什么和如何去干，都不会受到外界的干预，而在很大 程度上取决于自己。然而，在休闲旅行中经常发生的一窝蜂现象和休闲娱乐基础设施方面的种种缺 陷，却经常使休闲成为一种相似的、团体的行为方式，我们对此需要预先进行仔细的分析。 　　对现代休闲交通的要求     

Long-term wear and rolling contact fatigue behaviour of a conformal wheel profile designed for large radius curves

There are many reasons to optimise the wheel–rail interface through redesign or maintenance. Minimising wear and rolling contact fatigue (RCF) initiation on wheels and/or rails is often at the forefront of such considerations. This paper covers the design of a conformal wheel profile and its long-term wear and RCF performance to optimise the wheel–rail interface and subsequently reduce the occurrence of surface-initiated RCF on South Africa’s iron ore export line. A comparative study is performed using multibody dynamics simulation together with numerical wheel wear and RCF predictions. The advantages of a conformal wheel profile design are illustrated by evaluating the worn shape and resulting contact conditions of the conformal design. The conformal design has a steadier equivalent conicity progression and a smaller conicity range compared with the current wheel profile design over the wheel’s wear life. The combination of a conformal wheel profile design with 2?mm hollow wear and inadequate adherence to grinding tolerances often result in two-point contact, thereby increasing the probability of RCF initiation. The conformal wheel profile design proved to have wear and potential RCF benefits compared with the current wheel profile design. However, implementation of such a conformal wheel profile must be accompanied by improved rail grinding practices to ensure rail profile compliance.