184 research outputs found

    Are railways really that bad? An evaluation of rail systems performance in Europe with a focus on passenger rail

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    With a large number of railway development projects in Europe and worldwide, which once completed will be serving rail passengers of the future, this paper aims to take a step back and evaluate current railway systems performance. The objectives are to compare statistical data on various parameters of the railway system in a number of selected European countries and draw conclusions on the level of their performance when compared to the European average. Analyses of publically available statistical data, extracted from the Eurostat service at a European level will allow for a comparison of various indicators which influence the performance of the railway systems from an infrastructure and operational perspectives. The analyses will also allow identifying key performance indicators for the accurate assessment of the rail systems. The paper will highlight case studies for various parameters which are important to stakeholders of the railways, including infrastructure managers, rail operators, policy makers and the end users. This knowledge will be to the benefit of today’s railway industry as well as the rail systems of the future, as it will show trends drew upon existing data which might continue in the future

    Derailment risk and dynamics of railway vehicles in curved tracks: Analysis of the effect of failed fasteners

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    [EN] The effect of the fastener s failure in a railway track on the dynamic forces produced in the wheel-rail contact is studied using the simulation software VAMPIRE to assess the derailment risk of two different vehicles in two curves with distinct characteristics. First, a 3D-FEM model of a real track is constructed, paying special attention to fasteners, and calibrated with displacement data obtained experimentally during a train passage. This numerical model is subsequently used to determine the track vertical and lateral stiffness. This study evidences that although the track can practically lose its lateral stiffness as a consequence of the failure of 7 consecutive fasteners, the vehicle stability would not be necessarily compromised in the flawed zone. Moreover, the results reveal that the uncompensated acceleration and the distance along which the fasteners are failed play an important role in the dynamic behavior of the vehicle-track system, influencing strongly the risk of derailmentMorales-Ivorra, S.; Real Herráiz, JI.; Hernández Gracia, C.; Montalbán-Domingo, L. (2016). Derailment risk and dynamics of railway vehicles in curved tracks: Analysis of the effect of failed fasteners. Journal of Modern Transportation. 24(1):38-47. doi:10.1007/s40534-015-0093-zS3847241Iwnicki S (2006) Handbook of railway vehicle dynamics.CRC Press, Boca RatónJin XS, Wen ZF, Wang KY, Zhou ZR, Liu QY, Li CH (2006) Three-dimensional train-track model for study of rail corrugation. J Sound Vib 293:830–855Jin X, Wen Z, Xiao X (2007) A numerical method for prediction of curved rail wear. Multibody Sys Dyn 18:531–557Li W, Xiao G, Wen Z, Xiao X, Jin X (2011) Plastic deformation of curved rail at rail weld caused by train-track dynamic interaction. Wear 271:311–318Jin X, Wen Z (2008) Effect of discrete track support by sleepers on rail corrugation at a curved track. J Sound Vib 315:279–300Di Gialleonardo E, Bruni S, True H (2014) Analysis of the nonlinear dynamics of a 2-axle freight wagon in curves. Veh Syst Dyn 52(1):125–141Wang K, Liu P (2012) Lateral stability analysis of heavy-haul vehicle on curved track based on wheel/rail coupled dynamics. J Transp Technol 2:150–157Kurzeck B, Hecht M (2010) Dynamic simulation of friction-induced vibrations in a light railway bogie while curving compared with measurement results. Veh Syst Dyn 48:121–138Chen P, Gao L, Hao J (2007) Simulation study on parameters influencing wheel/rail wear in railway curve. China Railway Science 5Sun Y, Cole C, Boyd P (2011) A numerical method using VAMPIRE modelling for prediction of turnout curve wheel-rail wear. Wear 271(1–2):482–491Brabie D (2007) On derailment-worthiness in railway vehicle design. Analysis of vehicle features influencing derailment processes and consequences, PhD Thesis, Royal Institute of Technology, StockholmMatsumoto A, Sato Y, Ohno H, Shimizu M, Kurihara J, Saitou T, Michitsuji Y, Matsui R, Tanimoto M, Mizuno M (2014) Actual states of wheel/rail contact forces and friction on sharp curves—continuous monitoring from in-service trains and numerical simulations. Wear 314:189–197Wang L, Huang A, Liu G (2013) Analysis on curve negotiation ability of the rail vehicle based on SIMPACK. Adv Mater Res 721:551–555Eom BG, Lee H (2010) Assessment of running safety of railway vehicles using multibody dynamics. Int J Precis Eng Manuf 11(2):315–320Zhou L, Shen Z (2013) Dynamic analysis of a high-speed train operating on a curved track with failed fasteners. J Zhejiang Univ Sci A 14(6):447–458Xiao X, Jin X, Wen Z (2007) Effect of disabled fastening systems and ballast on vehicle derailment. J Vib Acoust 129:217–229Shi W, Cai C (2011) Influence of slab track fastener failure on track dynamic performance. In: Advances in environmental vibration-proceedings of the 5th international symposium on environmental vibration, Chengdu, pp 686–692Xiao X, Jin X, Deng Y, Zhou Z (2008) Effect of curved track support failure on vehicle derailment. Veh Syst Dyn 46(11):1029–1059Zakeri J, Fakhari M, Mirfattahi B (2012) Lateral resistance of railway track with frictional sleepers. Proc Inst Civ Eng Transp 165(2):151–155Gibert X, Patel V, Chellappa R (2015) Robust fastener detection for autonomous visual railway track inspection. In: IEEE Winter Conference on Applications of Computer Vision, Waikoloa Beach Hawai, pp 694–701Thompson D, Hemsworth B, Vincent N (1996) Experimental validation of the TWINS prediction program for rolling noise, part 1: description of the model and method. J Sound Vib 193(1):123–135Zakeri JA (2012) Lateral resistance of railway track. In: Perpinya DX (ed) Reliability and safety in railway. InTech Europe, Rijeka, pp 357–374Kernes RG, Edwards JR, Dersh MS, Lange DA, Barkan CP (2011) Investigation of the dynamic frictional properties of a concrete crosstie rail seat and pad and its effect on rail seat deterioration (RSD). Transportation Research Board 91st annual meeting. Railtec, Chicago, IllinoisCarrascal-Vaquero I (2006) Optimization and analysis of the behavior of fastener systems for Spanish high-speed railways. PhD Thesis, University of Cantabria, Santander (In Spanish)Sany J (1996) Another look at the single wheel derailment criteria. In: Proceedings of the IEEE/ASME Joint Railroad Conference, pp 17–22Koo J, Oh H (2014) A new derailment coefficient considering dynamic and geometrical effects of a single wheelset. J Mech Sci Technol 28(9):3483–3498UIC-Leaflet-518 (2009) Testing and approval of railway vehicles from the point of view of their dynamic behaviour-safety-track fatigue-ride quality. Railway Technical Publications, ParisUNE-EN14363:2007 (2007) Railway applications—testing for the acceptance of running characteristics of railway vehicles—testing of running behaviour and stationary tests. AENOR, Madri

    An empirical study of the variability in the composition of British freight trains

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    As part of the broader sustainability and economic efficiency agenda, European transport policy places considerable emphasis on improving rail’s competitiveness to increase its share of the freight market. Much attention is devoted to infrastructure characteristics which determine the number of freight trains which can operate and influence the operating characteristics of these trains. However, little attention has been devoted to the composition of the freight trains themselves, with scant published data relating to the practicalities of this important component of system utilisation and its impacts on rail freight viability and sustainability. This paper develops a better understanding of the extent to which freight train composition varies, through a large-scale empirical study of the composition of British freight trains. The investigation is based on a survey of almost 3,000 individual freight trains, with analysis at four levels of disaggregation, from the commodity groupings used in official statistics down to individual services. This provides considerable insight into rail freight operations with particular relevance to the efficiency of utilisation of trains using the available network paths. The results demonstrate the limitations of generalising about freight train formations since, within certain commodity groupings, considerable variability was identified even at fairly high levels of disaggregation

    Cardiovascular mortality and exposure to extremely low frequency magnetic fields: a cohort study of Swiss railway workers

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    <p>Abstract</p> <p>Background</p> <p>Exposure to intermittent magnetic fields of 16 Hz has been shown to reduce heart rate variability, and decreased heart rate variability predicts cardiovascular mortality. We examined mortality from cardiovascular causes in railway workers exposed to varying degrees to intermittent 16.7 Hz magnetic fields.</p> <p>Methods</p> <p>We studied a cohort of 20,141 Swiss railway employees between 1972 and 2002, including highly exposed train drivers (median lifetime exposure 120.5 μT-years), and less or little exposed shunting yard engineers (42.1 μT-years), train attendants (13.3 μT-years) and station masters (5.7 μT-years). During 464,129 person-years of follow up, 5,413 deaths were recorded and 3,594 deaths were attributed to cardio-vascular diseases. We analyzed data using Cox proportional hazards models.</p> <p>Results</p> <p>For all cardiovascular mortality the hazard ratio compared to station masters was 0.99 (95%CI: 0.91, 1.08) in train drivers, 1.13 (95%CI: 0.98, 1.30) in shunting yard engineers, and 1.09 (95%CI: 1.00, 1.19) in train attendants.Corresponding hazard ratios for arrhythmia related deaths were 1.04 (95%CI: 0.68, 1.59), 0.58 (95%CI: 0.24, 1.37) and 1.30 (95%CI: 0.87, 1.93) and for acute myocardial infarction 1.00 (95%CI: 0.73, 1.36), 1.56 (95%CI: 1.04, 2.32), and 1.14 (95%CI: 0.85, 1.53). The hazard ratio for arrhythmia related deaths per 100 μT-years of cumulative exposure was 0.94 (95%CI: 0.71, 1.24) and 0.91 (95%CI: 0.75, 1.11) for acute myocardial infarction.</p> <p>Conclusion</p> <p>This study provides evidence against an association between long-term occupational exposure to intermittent 16.7 Hz magnetic fields and cardiovascular mortality.</p

    Hair analysis for the detection of drug use – is there potential for evasion?

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    Background: Hair analysis for illicit substances is widely used to detect chronic drug consumption or abstention from drugs. Testees are increasingly seeking ways to avoid detection by using a variety of untested adulterant products (e.g. shampoos, cleansers) widely sold online. This study aims to investigate adulteration of hair samples and to assess effectiveness of such methods. Methods: The literature on hair test evasion was searched for on PubMed/MEDLINE, Psycinfo, and Google Scholar. Given the sparse nature of peer-reviewed data on this subject, results were integrated with a qualitative assessment of online sources, including user-orientated information/commercial websites, drug fora and ‘chat rooms’. Over four million web sources were identified in a Google search by using ‘beat hair drug test’ and the first 86 were monitored on regular basis and considered for further analysis. Results: Attempts to influence hair test results are widespread. Various ‘shampoos’, ‘cleansers’ among other products, were found for sale, which claim to remove analytes. Often advertised with aggressive marketing strategies, which include discounts, testimonials and unsupported claims of efficacy. However, these products may pose serious health hazards and are also potentially toxic. In addition, many anecdotal reports suggest that Novel Psychoactive Substances (NPS) are also consumed as an evasion technique, as these are not easily detectable via standard drug test. Recent changes on NPS legislations such as New Psychoactive Bill in the UK might further challenge the testing process. Conclusion: Further research is needed by way of chemical analysis and trial of the adulterant products sold online and their effects as well as the development of more sophisticated hair testing techniques
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