Understanding Leaf Chemistry and Effects on Low Adhesion

项目总结：英国的铁路网络每天负责400万次旅行(1)，预计这一数字在未来25年内将翻一番。随着全球对更可持续和更环保的旅行的持续追求，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上下班。树叶会形成一层有问题的“聚四氟乙烯”涂层，它会附着在铁路栏杆上，同时严重减少车轮在栏杆上滚动/滑动的摩擦力。轮轨界面的低附着会导致制动和牵引问题，并严重影响秋季期间的网络性能。据估计，对整个英国铁路行业的低附着力的年度成本估计超过1亿英镑(3)。这笔费用归因于；延误退款/赔偿、事故调查、维护维修（轮对重新剖析、更换损坏的轨道）、轨道旁植被管理等。该项目的主要目的是扩大对由叶子引起的低附着力的理解，包括不同叶子化学物质的影响，特定叶子掉落的时间和相关的天气条件。然后，这些数据将与其他低附着力的基础知识（来自RSSB项目的氧化物和少量水）一起使用，以开发改进的附着力指数预测。这种改进的附着力预测可以减少秋季的事故和延误，提高可靠性，并吸引铁路作为一种更环保的大众交通工具。这项工作将扩大目前正在进行的项目的范围，通过检查更多的叶子并引入实地方面，即摩擦评估、天气影响、叶子掉落和叶子夹带的信息，最后通过帮助开发粘附问题的预测。本项目的目标包括：确定英国铁路轨道上导致低附着问题的主要叶片类型：研究当前关于轮轨界面叶片污染的文献。调查铁路污染的行业报告，哪些是麻烦的叶子种类？哪些是麻烦的叶子种类？研究英国最常见的树木类型（仅落叶类）。查找有关叶片问题和关键绩效指标的操作数据。收集有关秋季天气情况及落叶的资料。收集整个秋季的摩擦数据，与天气数据相关联。探讨不同化学分析技术对茶叶的影响，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。为测试准备叶子：收集叶子并安全储存直到需要。使用与文献中相同的方法制备样品。对选定的叶子进行化学分析：联系相关员工进行所需机器的培训，如；FT-IR（傅里叶变换红外光谱），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。进行不同叶片和叶片层的摩擦学测试：接受所需钻机/机械的培训，例如；SUROS（谢菲尔德大学滚动滑动）钻机，UMT（通用机器摩擦计），FSR（全尺寸钻机）和摆锤钻机。进行与文献中所述相当的摩擦学试验。参考文献；乘客——铁路网。(在线)。[2018年2月12日访问]。可从：https://www.networkrail.co.uk/communities/passengers/2.FULFORD, c.f.低粘附研究综述。2004.3.AWG, RSSB。附着力手册6.0版[在线]。2018. [2018年5月29日获取]。可从：https://www.rssb.co.uk/rgs/oodocs/rdg-awg ma

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