Key aspects on the behaviour of the ballast and substructure of a modern railway track: research-based practical observations in Finland

This paper presents an overview on the wide-ranging track structure studies at the Tampere University of Technology (TUT), Finland dealing with the key aspects of track geotechnics related to high-speed passenger traffic on ballasted tracks. Special attention is paid to ballast and sub-ballast, while also considering frost action, embankment stability, track stiffness, track geometry and transition zones. As a result, this paper states that understanding the ballast degradation mechanism and its consequences and assessment of its condition occupy an important role in the construction and maintenance of a smooth high-speed rail line. The choices related to building the sub-ballast also have a dramatic impact on later track deformations and maintenance needs. In cold climate, especially where seasonal frost occurs, understanding and taking into account the frost action mechanism is crucial. Especially in the maintenance and rehabilitation planning of existing tracks, high-class analyses of ground penetrating radar data and its integrated analysis with other data can yield considerable benefits.     

高速列车车轮多边形对车内噪声的影响

研究目的：研究高速列车车轮多边形特征对轮轨噪声和车内噪声的影响规律,讨论目前国内高速列车车轮镟修指标的不足,为高速列车车轮镟修方法的优化改进提供科学依据。创新要点：系统分析高速列车车轮多边形阶次、幅值和相位等参数对车内噪声的影响规律;提出车轮镟修中仅考虑车轮径跳作为限值是不够的。研究方法：1．基于线路试验,初步分析高速列车车轮多边形状态对车内噪声的影响,进而对车轮多边形特征进行剖析;2．基于带通滤波和快速傅里叶变换,使用MATLAB程序生成不同阶次、幅值和相位的车轮多边形粗糙度数据;3．基于TWINS轮轨噪声原理,使用HWTNS预测含有不同车轮多边形特性的轮轨噪声;4．基于混合有限元-统计能量分析（FE—SEA）方法,建立高速列车客室端部车内噪声预测模型,预测车内噪声;5．通过分析车轮多边形参数、车轮径跳和车内噪声之间的相互关系,研究目前的高速列车车轮镟修指标是否合适。重要结论：1．高速列车车轮径跳值相同,但车轮多边形状态不同时,轮轨噪声与车内噪声有明显差异;2．当车轮多边形幅值相同时,高阶多边形可以引起更高的轮轨噪声和车内噪声;3．改变车轮多边形的相位,可以获得不同的车轮径跳值,但是对轮轨噪声和车内噪声几乎没有影响。     

高速铁路运营过程中的关键问题：轮轨磨耗等

随着高速铁路运营里程和列车运营速度的不断增长,出现了一些和列车轨道耦合大系统密切相关的关键科学和技术问题。这些问题不仅影响到列车的运行品质,甚至威胁到安全运行,是当前高速铁路运用和发展中急需解决的问题。本文系统描述了高速铁路在运营过程中所出现的一些关键科学和技术问题,并述评了全世界有关这些问题的研究进展、现状和不足之处,提出了今后有利于认识和解决这些问题的发展方向。在长期高速运营的铁路大系统环境中,这些问题的形成的机理、发生、发展过程和预防措施的研究,需要从列车／轨道耦合大系统运营环境（速度、路况、气候和运用维修）、系统的自身参数匹配、材料选用和运营成本等全面系统考虑,并从理论、技术、工艺、监控和维修等方面解决。     

基于铁谱分析系统的机床健康检测

对某机床厂的龙门导轨磨床MMA52160A利用铁谱分析技术的油样进行定期检测,及时地掌握龙门导轨磨床的磨损状况。通过实验与分析发现,在检测时间段内导轨磨床内部存在着正常磨损、切削磨损、滚滑复合磨损磨粒以及铁的氧化物,在数量上以正常磨损居多,其它类型磨粒数量较少,可以判断导轨磨床仍处于正常运行状态。 实验表明,铁谱分析技术可以对机床的运行状态进行预报故障;同时,可合理地确定机床的换油周期,节省油料,做到科学润滑,以延长龙门导轨磨床的使用寿命。     

固定辙叉区轮轨静态接触几何关系计算

针对固定辙叉特殊的轨线布置及复杂的轮轨接触关系,建立固定辙叉区轮轨接触几何关系算法,分析固定辙叉区沿辙叉走行方向主要接触参数的变化规律以及各关键断面轮轨接触点变化情况。结果表明:在辙叉轮载过渡段轮轨接触参数变化规律复杂,结构不平顺变化幅值最大且波长较短;轮对横移量增加,轮轨接触几何参数增大,轮轨动力作用增强;辙叉咽喉区和轮载过渡段辙叉侧轮轨接触点变化存在突变。提出应合理设计辙叉区轮载过渡段结构参数,优化轮轨接触几何关系,进而改善列车通过时辙叉的受力性能。     

Numerical investigation on wheel-turnout rail dynamic interaction excited by wheel diameter difference in high-speed railway

The wheel-rail relationship in turnout is more complicated than that in ordinary track. Profile wear and machining errors of the wheelset cause deviations of the rolling radius on different wheels. Therefore, wheelsets move to the direction of smaller diameter wheels in search of a new stable state and to change the condition before entering the turnout. The main aim of the present work is to examine the wheel-turnout rail dynamic interaction combined with the static contact behaviour. Calculations are performed on a high-speed vehicle CRH2 and the No. 12 turnout of the passenger dedicated line. The wheel-turnout contact geometric relationship and normal contact behaviour under wheel diameter difference are assessed by the trace principle and finite element method. A high-speed vehicle-turnout coupling dynamic model is established based on SIMPACK software to analyse the wheel-rail dynamic interaction, riding comfort, and wear. Both the wheel diameter amplitudes and distribution patterns are accounted for. The simulation shows that wheel diameter difference can greatly disturb the positions’ variation of wheel-rail contact points and affect the normal contact behaviour on switch rails by changing the load transition position. The effect of wheel diameter difference on wheel-turnout rail dynamic interaction can be divided into three according to its amplitude: when the wheel diameter difference is within 0–1.5 mm, the wheel flange comes into contact with the switch rail in advance, causing a rapidly increased lateral wheel-rail force; when it is within 1.5–2.5 mm, trains are subject to instability under equivalent in-phase wheel diameter difference; when it is larger than 2.5 mm, the continuous flange-switch rail contact helps strengthen the vehicle stability, but increases the wheel-rail wear. It is recommended to control the wheel diameter difference to within 2.5 mm but limit it to 2 mm if it is distributed in-phase.     

Dynamic analysis of a high-speed train operating on a curved track with failed fasteners

A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners. The model considers a high-speed train consisting of eight vehicles coupled with a ballasted track. The vehicle is modeled as a multi-body system, and the rail is modeled with a Timoshenko beam resting on the discrete sleepers. The vehicle model considers the effect of the end connections of the neighboring vehicles on the dynamic behavior. The track model takes into account the lateral, vertical, and torsional deformations of the rails and the effect of the discrete sleeper support on the coupling dynamics of the vehicles and the track. The sleepers are assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. The train model couples with the track model by using a Hertzian contact model for the wheel/rail normal force calculation, and the nonlinear creep theory by Shen et al. (1984) is used for wheel/rail tangent force calculation. In the analysis, a curved track of 7000-m radius with failed fasteners is selected, and the effects of train operational speed and the number of failed fasteners on the dynamic behaviors of the train and the track are investigated in detail. Furthermore, the wheel/rail forces and derailment coefficient and the wheelset loading reduction are analyzed when the high-speed train passes over the curved track with the different number of continuously failed fasteners at different operational speeds. Through the detailed numerical analysis, it is found that the high-speed train can operate normally on the curved track of 7000-m radius at the speeds of 200 km/h to 350 km/h.     

高速磁浮轨道不平顺测试及分析

研究目的：提出高速磁浮轨道不平顺处理方法,分析不平顺特征,拟合形成轨道谱,为线路卒问维护提供参考。创新要点：实现了对高速磁浮轨道不平顺的提取,确定了轨道谱参数。研究方法：基于惯性基准法,运用数字信号处理方法实现对轨道不平顺的提取,采用最小二乘法拟合得剑定子向和导向面七参数轨道谱。重要结论：定子面和导向面分别在5-100m和10-100m波长范围内平顺性状态较好,由功能件安装等引起的1-5m和1—10m波长范围内的偏差应严格控制。     

Development and validation of a model for predicting wheel wear in high-speed trains

In this paper, we present a comprehensive model for the prediction of the evolution of high-speed train wheel profiles due to wear. The model consists of four modules: a multi-body model implemented with the commercial multi-body software SIMPACK to evaluate the dynamic response of the vehicle and track; a local contact model based on Hertzian theory and a novel method, named FaStrip (Sichani et al., 2016), to calculate the normal and tangential forces, respectively; a wear model proposed by the University of Sheffield (known as the USFD wear function) to estimate the amount of material removed and its distribution along the wheel profile; and a smoothing and updating strategy. A simulation of the wheel wear of the high-speed train CRH3 in service on the Wuhan-Guangzhou railway line was performed. A virtual railway line based on the statistics of the line was used to represent the entire real track. The model was validated using the wheel wear data of the CRH3 operating on the Wuhan- Guangzhou line, monitored by the authors’ research group. The results of the predictions and measurements were in good agreement.     

绝对和相对小车结合法在长轨精调技术中的应用研究

高铁无砟轨道在长轨铺设完后需要对线路进行全面静态调整,将轨道几何尺寸调整到允许误差范围内,使线路轨道平顺性充分满足高铁联调联试前提要求.由于过程中消除轨道病害时间短、任务重,快速查找病害位置和消除方法便成为关键.位于高寒、高海拔、风沙环境下的兰新铁路LXS-2标段及时研究并采用绝对和相对小车结合法轨道调整技术,不仅提高...     

BTJ-5陀螺全站仪在轨道交通工程测量中的应用

在介绍下架式陀螺全站仪定向原理的基础上,结合BTJ-5陀螺全站仪在广州市城市轨道交通11号线地下隧道控制测量中的应用,分析高精度全自动陀螺全站仪在轨道交通工程测量中的作业流程及注意事项,并对影响陀螺仪定向精度的因素及应对措施进行归纳总结,为高精度陀螺全站仪在相关领域的推广应用提供一定的技术参考。     

ZPW-2000A型电气绝缘节漏码信号问题研究

论述了电气绝缘节的基本工作原理,说明无绝缘轨道电路绝缘节通过串并联谐振实现绝缘隔离的基本机理.其次阐述了轨道小轨道与主轨道电路之间的基本关系及缩短调谐区死区段的基本情况,同时针对铁路区间自动闭塞信号设备ZPW-2000A无绝缘轨道电路,在距电气绝缘节（调谐区）送电端第3个电容左右处地点,机车信号接收器收到的漏码信号达到最大值;第3个电容开路时,小轨道电路接收电压值下降最大等现象进行了理论研究,探寻上述现象的理论依据.     

WEAR PERFORMANCE AND MECHANISM OF ZINC-ALUMINUM（ZA27）ALLOY

ＷＥＡＲＰＥＲＦＯＲＭＡＮＣＥＡＮＤＭＥＣＨＡＮＩＳＭＯＦＺＩＮＣ－ＡＬＵＭＩＮＵＭ（ＺＡ２７）ＡＬＬＯＹＳｕＨｕａｑｉｎ（苏华钦）ＳｈｉＺｈｏｎｇｌｉａｎｇ（施忠良）ＺｈｕＭｉｎｇｆａｎｇ（朱鸣芳）（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎ...     

城市轨道交通换乘导乘信息系统优化设计研究

随着轨道交通线网的日益完善,越来越多的人们选择轨道交通出行,这也给轨道交通换乘带来了巨大压力,完善的导乘信息系统可以缓解换乘压力。新百广场站是石家庄轨道交通目前唯一的换乘站,承担着重要的换乘任务。通过调研新百广场站导乘信息系统现状,发现存在的相关问题,提出针对该站导乘问题的优化措施。极大地缩短了乘客在车站内停留的时间,提高了换乘以及进出站的效率,使新百广场站导乘信息系统充分发挥其作用。     

Investigation of differential movement at railroad bridge approaches through geotechnical instrumentation

Railway transitions experience differential movements due to differences in track system stiffness, track damping characteristics, foundation type, ballast settlement from fouling and/or degradation, as well as fill and subgrade settlement. This differential movement is especially problematic for high speed rail infrastructure as the ??bump?? at the transition is accentuated at high speeds. Identification of different factors contributing towards this differential movement, as well as development of design and maintenance strategies to mitigate the problem is imperative for the safe and economical operation of both freight and passenger rail networks. This paper presents the research framework and initial instrumentation details from an ongoing research effort at the University of Illinois at Urbana-Champaign. Three bridge approaches experiencing recurrent geometry problems were instrumented using multidepth deflectometers (MDDs) and strain gages to identify different factors contributing to the development of differential movements.     

Quasi-static-model-based wear analysis of helical gears

A quasi-static wear model for helical gears is proposed based on finite element method and Archard’s formula to investigate the wear characteristics of tooth surface in real operation conditions. The numerical simulation reveals that the wear depth distributes unevenly along the tooth lead and varies along the tooth profile. The surface wear depth claims its minimal value at the pitch circle and reaches its maximal value near the tooth root of the pinion. The effects of misalignment on wear depth are further investigated to provide useful information for gear designers. The numerical simulation reveals that the vertical misalignment is more influential than the parallel misalignment on the gear wear depth. Therefore, to eliminate the negative effects of misalignment, the misalignment should be strictly controlled.     

基于AutoCAD的海上平台导管架单件图自动生成系统研究与开发

系统服务于火焰数控切管机切割海上平台导管架管件,系统输入为海洋平台的结构单线图,系统输出为导管架切割单件图。通过直接识别和提取加工所需要的参数信息,自动计算切管机所需要的各种几何参数,最后根据得到的几何参数计算相贯线并绘制出导管架单件图。该系统属于基于图形的自动编程系统,是CAD/CAM一体化技术的一种应用。     

BIM技术在燃气输配场站运维管理中的应用研究

针对当前燃气输配场站运维管理缺少有效的协同管理平台、信息化水平低的问题,将BIM技术引入到燃气输配场站运维管理之中.结合唐山市某燃气输配场站实际工程案例,进行燃气输配场站BIM运维模型的构建,并对基于BIM的输配场站的运维信息管理、设施设备维保管理、管线综合管理、资产管理等方面进行应用研究.研究结果表明,将BIM技术应...     

On－Line Identification of Grinding Burn and Wheel Wear Based on Grinding Chips Thermal Flow

Ｏｎ－ＬｉｎｅＩｄｅｎｔｉｆｉｃａｔｉｏｎｏｆＧｒｉｎｄｉｎｇＢｕｒｎａｎｄＷｈｅｅｌＷｅａｒＢａｓｅｄｏｎＧｒｉｎｄｉｎｇＣｈｉｐｓＴｈｅｒｍａｌＦｌｏｗＳｈｉＪｉｎｆｅｉ（史金飞）ＺｈａｎｇＸｉａｏｌｉｎｇ（张晓玲）ＺｈｏｎｇＢｉｎｇｌｉｎ（钟...     

Theoretical investigation into the effect of rail vibration dampers on the dynamical behaviour of a high-speed railway track

Installation of rail vibration dampers (rail dampers for short) onto rails between sleepers is one of the measures to control rail noise generation and roughness growth. Amid the rapid expansion of high-speed and underground railway networks in China, many suppliers are actively marketing and promoting their products, often giving confusing information. In this paper, a parametric study is used to investigate the effect of rail dampers on the dynamical behavior of a Chinese high-speed railway track. The Fourier transform-based method developed for analyzing dynamics of a railway track as an infinitely long periodic structure, with or without rail dampers, is applied in the investigation. It is hoped that results in this paper can help develop the understanding of the working mechanism of rail dampers, and provide useful information for product design and application.