Understanding Leaf Chemistry and Effects on Low Adhesion

项目摘要：英国的铁路网每天载客400万人次，预计这一数字在未来25年内将翻一番。随着全球继续推动更可持续、更环保的出行，铁路公司和运营商面临着更大的压力，需要提高安全性和可靠性，并鼓励通勤者改用铁路通勤。树叶形成了一种有问题的“特氟龙”涂层，它附着在铁轨头上，同时严重减少了车轮在其上滚动/滑动的摩擦力(2)。轮轨界面的低粘附性会导致制动和牵引力问题，并在秋季显著影响网络性能。据估计，低粘着对整个GB钢轨行业的年成本估计超过1亿GB(3)。这一成本归因于：延误、事故调查、维护维修(轮对重新配置、更换损坏的轨道)、轨道旁植被管理等造成的退款/补偿。该项目的主要目的是扩大对树叶造成的低粘附性的理解，以包括不同树叶化学物质、特定树叶掉落的时间和相关天气条件的影响。然后，这些数据将与低附着力的其他基础知识(来自RSSB关于氧化物和少量水的项目)一起使用，以开发改进的附着力指数预测。这种改进的粘合预测可以减少秋季的事故和延误，并提高可靠性，并呼吁铁路作为一种更环保的公共交通工具。这项工作将扩大目前正在进行的项目的范围，通过检查更多的树叶，并引入现场方面，即摩擦评估、天气影响、树叶掉落和树叶卷吸的信息，最后通过帮助开发粘合问题的预测。这项项目的拟议目标包括：确定英国轨道上存在的导致低粘着问题的主要叶片类型：研究关于轮轨界面中叶片污染的最新文献。调查关于轨头污染的行业报告，什么是最麻烦的树叶种类？研究英国最常见的树木类型(仅落叶树种)。寻找有关树叶问题和关键性能指标(KPI)的操作数据。收集有关秋季天气条件和落叶的数据。收集整个秋季的摩擦数据，以与天气数据相关联。调查关于树叶的化学分析技术：研究不同化学分析技术的优缺点。研究文献中使用的化学分析。为分析技术找到理想的样品状态。为测试准备树叶：收集树叶并安全储存，直到需要与文献中的方法相同。对选定的树叶进行化学分析：联系相关工作人员进行所需机器的培训，如；FT-IR(傅立叶变换红外光谱)、XPS(X射线光电子能谱)和LRS(激光拉曼光谱)。进行化学分析并收集数据。对不同的树叶和树叶层进行摩擦学测试：在所需的钻机/机械上进行培训，如：Suros(谢菲尔德大学滚动滑动)试验机、UMT(万能机械摩擦仪)、FSR(全尺寸试验机)和钟摆试验机。进行与文献相当的摩擦学试验。参考；1.乘客-网络轨道。[在线]。[2018年2月12日访问]。可从：https://www.networkrail.co.uk/communities/passengers/2.FULFORD，C.F.低附着力研究综述。2004.3.AWG，RSSB。附着力手册6.0版[在线]。2018年。[2018年5月29日访问]。可从：https://www.rssb.co.uk/rgs/oodocs/rdg-awg MA获得

Project summary:The rail network in the UK is responsible for 4 million journeys daily (1), with this number predicted to double over the next 25 years. As the global drive for more sustainable and environmentally friendly travel continues, rail companies and operators are being put under more pressure to improve safety and reliability, as well as encourage commuters to switch to rail for their commute. Leaves create a problematic "Teflon like" coating which adheres to the railhead while severely reducing friction to the wheels which roll/slide over it (2).Low adhesion in the wheel-rail interface can and does cause problems for braking and traction and significantly affects network performance in the Autumn period. The annual cost estimation of low adhesion to the whole of GB rail industry has been estimated to be in excess of £100 million (3). This cost is attributed to; refunds/compensation due to delays, incident investigation, maintenance repairs (wheelset re-profiling, replacing broken track), trackside vegetation management and more.The main aim of the project is to widen the understanding of low adhesion caused by leaves to include effects of different leaf chemistries, times that particular leaves fall and related weather conditions. This data will then be used with other fundamental knowledge of low adhesion (from RSSB projects on oxides and small amounts of water) to develop an improved adhesion index prediction. This improved adhesion prediction could reduce incidents and delays in the autumn period as well as improve reliability and appeal rail as a more environmentally friendly means of mass transportation.This work will expand the scope of the project currently under way by examining more leaves and bringing in the field side, i.e., friction assessment, effects of weather, information on leaf fall and entrainment of leaves and finally by helping to develop the prediction of adhesion problems.The aims proposed for this project include;Identify the main types of leaves present on UK rail track that cause low adhesion problems:Research current literature regarding leaf contamination in the wheel-rail interface.Investigate industry reports on railhead contamination, what are the more and less troublesome leaf species?.Research most common types of trees in the UK (deciduous only).To find operational data on the leaf problems and Key Performance Indicators (KPIs).Collect data about autumn weather conditions and leaf fall.Collect friction data throughout the autumn period to correlate with weather data.To investigate the chemical analysis techniques regarding leaves:Research the advantages and disadvantages of different chemical analysis techniques.Research the chemical analysis used in the literature.Find the ideal sample state for analysis techniques.Prepare the leaves for testing:Collect leaves and store safely until required.Prepare samples using the same method found in the literature.Carry out chemical analysis of the selected leaves:Contact relevant members of staff for training on required machines such as; FT-IR (Fourier Transform-Infrared Spectroscopy), XPS (X-ray Photoelectron Spectroscopy) and LRS (Laser Raman Spectroscopy).Carry out chemical analysis and collect data.Carry out tribological tests of the different leaves and leaf layers:Become trained on required rigs/machinery such as; SUROS (Sheffield University ROlling Sliding) rig, UMT (Universal Machine Tribometer), FSR (Full-Scale Rig) and Pendulum rig.Carry out tribological tests comparable to those in the literature.References;1.Passengers - Network Rail. [online]. [Accessed 12 February 2018]. Available from: https://www.networkrail.co.uk/communities/passengers/2.FULFORD, C. F. Review of low adhesion research. 2004.3.AWG, RSSB. Adhesion Manual Edition 6.0 [online]. 2018. [Accessed 29 May 2018]. Available from: https://www.rssb.co.uk/rgs/oodocs/rdg-awg ma