Tree fall onto railway lines puts passengers at risk and causes large economic losses due to disruption of train services and damage to infrastructure. Railway lines in Germany are vulnerable to tree ...fall because of the large number of trackside trees that exist in that country with approximately 70% of all railway lines being tree-lined. In this paper we first tested whether a hybrid-mechanistic tree wind damage model, ForestGALES, could identify the sections of the railway network affected by tree fall in two federal states of Germany, Northrhine-Westphalia (NRW) and Thuringia (TH). We secondly tested whether the model, in combination with meteorological forecast models, could predict where tree fall occurred during a damaging windstorm. We used information on tree characteristics derived from LiDAR and aerial photography along the railway line network in NRW and TH to calculate the critical wind speed (CWS) at which damage is expected to happen for every individual tree as a function of its size and species, and the underlying soil. The railway network was then divided into 500 m sections and the statistics of the CWS, tree height, and species composition (broadleaf/conifer mix) within each section were calculated. Analysis of past tree fall events recorded by Deutsche Bahn AG (DB) showed that there was a significantly lower minimum CWS and significantly greater maximum tree height in sections that had recorded damage. In a second step we compared the calculated CWS values for all trees against downscaled wind speed assessments across the two federal states during Storm Friederike (named Storm David internationally) on 18 January 2018 and tested the ability of the model to discriminate sections with recorded damage during the storm. Excellent model discrimination was found with an AUC value of 0.82 and an overall model accuracy of 74.2%. The first test showed that the ForestGALES model with precise individual tree information can identify the sections of a railway network most vulnerable to tree fall. The second analysis showed, for the one storm tested, that the ForestGALES model when combined with predicted storm wind speeds can identify the most probable sections of the railway network to experience tree fall during an approaching damaging storm. Such information could be of value in firstly planning remedial work along railway lines, and secondly preparing the railway network ahead of a major storm.
•Tree fall is a major hazard to the railway network in Germany.•A mechanistic model could identify sections of a railway most at risk of tree fall.•The model identified sections likely to suffer tree fall prior to a storm.•Sections with tree fall had trees with significantly greater maximum heights.•The model can be used to identify sections requiring remedial action.
The purpose and objectives of this work are to consider the factors that determine a socio-economic efficiency of building High-speed Railway Lines (HSRL), conducting their systematization, analysis ...of effects that occur during the operation of high-speed rail transport, their essences, a mechanism of occurrence, a positive impact on economy. A scientific novelty of the research lies in the author’s attempt to justify a feasibility of creating high-speed transport even in regions with a population density that does not provide a quick payback of invested funds, conducting a classification of effects of HSRL, their detailed consideration. Provisions and conclusions of this work allow us more fully and objectively establish a social significance of HSRL, enrich design methodology and perhaps even accelerate an execution of existing projects in Russia, what characterizes its practical significance. Using analytical, logical, hypothetical and axiomatic research methods of research the current provisions in scientific literature and practice concerning developments in a field of creating high-speed rail transport, author makes an attempt to supplement and clarify the meaningful meaning of a socio-economic justification of effectiveness of HSRL.
Sustainability - declined in social, environmental, and spatial forms - is a prerogative of rail transport. Hence, railway systems, with their low impact and high inclusivity, are the solution Europe ...is aiming at. However, some non-electrified secondary lines were suspended in recent years in different countries, including Italy, for economic and political choices. The line under investigation is the Saluzzo-Savigliano (Piedmont, Italy) for which the solution of forcing traffic to the road created queues, congestion, and an increase in local, besides a loss in the actual use of the time by travelers. This paper aims at providing a decision support method to drive the modal shift to the rail in low-traffic lines through innovation, simulating operation on the aforementioned line and evaluating consumption and emissions – in a WTW approach - of three different types of train: the diesel Minuetto, thus taking over the past operation, the tram-train, whose capacity is adequate to the demand, and the fuel cell train that should enter into circulation in Italy from 2023. To minimise consumption (kWh/km), an optimisation of the running curves is being suggested and operation is analysed with the use of a custom simulator; a comparison of the specific energy consumption (kWh/pass·km) and the emissions are thereafter proposed. Consequently, a multi-criteria analysis using Electre methodology is applied to assess which option is more convenient on the given route, performing also a sensitivity analysis to highlight the improvements to be made to obtain an optimal solution that is convenient both for railway undertaking and the end-user. The convenience of low-traffic railway lines is an issue to be solved to achieve a modal shift towards inclusive, economic, and environmental-friendly public transport and to increase the resilience of the involved area at the foot of Monviso, providing tourism development opportunities and efficient services for commuters, possible only by leveraging technological innovations.
The pressure to achieve a higher speed of train operation has increased in the last few years due to the development of high-speed railway lines. In the presence of soft soils, this speed increase is ...not possible without undertaking soil improvement measures, since the critical speed is lower than the desired speed of train operation. One of the most widely used soil improvement techniques is that of stone columns. In relation to these is the concept of critical length which, up to now, has only been studied for static cases. This research focuses, for the first time, on the enhancement of the critical speed in high-speed railways with stone columns and with special reference to critical length. Moreover, others parameters such as: maximum rail displacement and Dynamic Amplification Factor (DAF) are also studied. Analysing three profiles of ground representative of soft soils, it can be observed how the effect of the stone columns on critical speed is relevant, showing that critical length is different with respect to the three parameters above, the most restrictive one being that which corresponds to the critical speed. The influence of other parameters on the critical length and on the effectiveness of stone columns, such as the area replacement ratio, the dynamic pressure bulb and the existing soil stiffness is analysed and discussed.
Railways are an efficient transport mean with lower energy consumption and emissions in comparison to other transport means for freight and passengers, and yet there is a growing need to increase ...their efficiency. To achieve this, it is needed to accurately predict their energy consumption, a task which is traditionally carried out using deterministic models which rely on data measured through money- and time-consuming methods. Using four basic (and cheap to measure) features (train speed, acceleration, track slope and radius of curvature) from MetroValencia (Spain), we predicted the traction power using different machine learning models, obtaining that a random forest model outperforms other approaches in such task. The results show the possibility of using basic features to predict the traction power in a metropolitan railway line, and the chance of using this model as a tool to assess different strategies in order to increase the energy efficiency in these lines.
Ссылка для цитирования: Тарасов В.А., Султанмагомедов Т.С., Султанмагомедов С.М. Изучение проблемы потери устойчивости поперечного сечения магистральных газопроводов в защитных футлярах под ...автомобильными и железными дорогами в результате увеличения объема замерзающей воды в межтрубном пространстве // Известия Томского политехнического университета. Инжиниринг георесурсов. – 2022. – Т. 333. – № 4. – С. 93-104.
Актуальность исследования обусловлена необходимостью снижения риска аварий на переходах магистральных газопроводов, проложенных в защитных футлярах под автомобильными и железными дорогами – одних из наиболее опасных и ответственных участков. Лед, образовавшийся в межтрубном пространстве при наличии сезонно промерзающих и оттаивающих грунтов или при перекачке газа при отрицательной температуре совместно с некачественной установкой торцевых уплотнений, может привести к смятию поперечного сечения газопровода, тем самым повышая риск аварии на данном участке. Проводимые исследования позволят заранее изучить потенциально уязвимые участки переходов с помощью компьютерного моделирования и предусматривать для них комплекс защитных мер. Цель: оценка возможности повреждения магистральных газопроводов, проложенных в защитных футлярах, льдом, который образовался в межтрубном пространстве; обоснование дополнительных мер и рекомендаций, направленных на обеспечение безопасной эксплуатации подземных переходов магистральных газопроводов под автомобильными и железными дорогами. Объекты: участки магистральных газопроводов, проложенные в защитных футлярах под автомобильными и железными дорогами в условиях сезонно оттаивающего и промерзающего грунта вблизи защитного футляра или транспортирующие газ при отрицательной температуре. Методы: математическое моделирование, моделирование методом конечных элементов, методы строительной механики и сопротивления материалов, планирование эксперимента. Результаты. Определена возможность повреждения магистральных газопроводов, проложенных в защитных футлярах, льдом, который образовался в межтрубном пространстве; предложена математическая модель определения давления, возникающего в межтрубном пространстве вследствие увеличения объема замерзающей воды, и проверена ее адекватность с использованием программного комплекса ANSYS на примере газопровода 219×6 мм и защитного футляра 325×12 мм; обозначены рекомендации для вновь проектируемых газопроводов и их переходов, а также для уже существующих.
The relevance of the study is caused by the need to reduce the risk of accidents at the crossings of trunk gas pipelines laid in protective cases under highways and railway lines – one of the most ...dangerous and responsible sections. Ice formed in the inter-pipe space in the presence of seasonally freezing and thawing soils or when pumping gas at negative temperature together with poor-quality installation of end sealing cuffs can lead to stability loss of the gas pipeline cross-section, thereby increasing the risk of an accident at this site. The conducted research will allow us to investigate potentially vulnerable sections of crossings in advance using computer modeling and provide for them a set of protective measures. The aim of the research is to assess the possibility of damage to trunk gas pipelines laid in protective cases by ice formed in the inter-pipe space; justify the additional measures and recommendations aimed at ensuring the safe operation of underground crossings of trunk gas pipelines under highways and railway lines. Objects: sections of trunk gas pipelines laid in protective cases under highways and railway lines in seasonally thawing and freezing soil near the protective case or transporting gas at a negative temperature. Methods: mathematical modeling, finite element modeling in the ANSYS software package, methods of structural mechanics and resistance of materials, experiment planning. Results. The possibility of damage to trunk gas pipelines laid in protective cases by ice formed in the inter-pipe space was determined; a mathematical model for determining the pressure arising in the inter-pipe space due to increase in freezing water volume was proposed and its adequacy was verified using the ANSYS software package on the example of a 219×6 mm gas pipeline and a 325×12 mm protective case; recommendations for newly designed gas pipelines and their transitions, as well as for existing ones, were indicated.
This paper presents a case study on the subgrade settlements of four national railway lines induced by twin shield tunnel excavations. The development characteristics of subgrade settlements can be ...divided into three stages. The monitoring data indicate that subgrade settlements increase gradually before the shield machine crossing the monitoring region, then increase sharply during the shield machine crossing, and finally approach to be stable after the shield machine crossing. Immediately splicing the segments into rings, implementing the compensation and secondary grouting facilitate the control of subgrade settlements. Operational parameters play a crucial role in controlling the subgrade settlements. The effects of the operational parameters of the shield machine on the subgrade settlements are analyzed. The investigation reveals that excessive shield driving velocity causes large subgrade settlements, accompanied by the sudden reduction of rotation torque and total thrust. The excavated earth volume affects the subgrade settlements insensitively because of its easily controlling. Synchronous grouting volume can rise the existing subgrade if not controlled appropriately. Great subgrade settlements cause large earth pressures to be exerted at the chamber. Some valuable references and guidance are given through this paper for the operational parameter setting of shield machines and deformation control of multiple railway lines due to the shield tunnel excavation beneath.
•Disused railways have potential as non-motorised territorial structuring axes.•The analysis method enables to understand disused railway as complex systems.•Areas, where similar guidelines can be ...implemented, have been identified.
The thousands of kilometres of disused railway lines that make up a fascinating body of heritage have been the subject of studies by several authors over recent decades. Several interventions for their reuse and reconversion have been carried out. However, there is a mismatch between theoretical and practical achievements. This research claims that an analysis of the railway lines under discussion should develop a comprehensive vision in order to establish common criteria for their preservation and for future interventions. As such, the objective of this paper is to create a methodological proposal for the analysis of disused railway lines as complex systems, thus demonstrating their potential as part of situated proposals for sustainable development. Accordingly, a Comprehensive Analysis Method (CAM) is created based on three theoretical and methodological underpinnings: disused railways as heritage systems; former linear infrastructures as non-motorised axes; and a balance between transport and other land uses around former railway nodes. The conclusions make reference to the potential of disused railways as territorial structuring systems, including both the potential of the linear infrastructure and the potential of the railway nodes, in order to encompass repurposing beyond the current greenways while continuing to promote the preservation of railway heritage. Both general strategies and specific action points have been identified for the repurposing of disused railway infrastructure. The proposed methodology has been applied in the case study of the Vasco-Navarro Railway, identifying strategic points in the infrastructure and areas where specific strategies can be implemented.
PDF
