Railway Section Research Articles

Analysis of Environmental Vibrations in Suburban Railways Affected by Adjacent Bidirectional Tunnels

Train-induced environmental vibrations are a common issue in urban rail transit systems, particularly in suburban railways operating at high speeds, where the impact of these vibrations is more pronounced. This presents significant challenges for urban planners and engineers. Existing research has mainly focused on the impact of single tunnel structures on ground vibrations, with limited understanding of the vibration propagation characteristics of adjacent bidirectional tunnels. To address this gap in knowledge, this study investigates the ground vibration attenuation characteristics induced by train operations in the underground sections of suburban railways, with a focus on the amplification effects of adjacent tunnels on ground vibrations. The results show that the vibrations induced by the trains are concentrated in the 20–50 Hz frequency range and exhibit similar characteristics in all directions. The maximum vertical vibration acceleration and peak acceleration occur directly above the train tunnel. Additionally, adjacent tunnels significantly amplify the maximum peak acceleration at measurement points in directions perpendicular to the track, including both horizontal and vertical directions. Furthermore, the soil within the adjacent tunnels also exhibits amplification of the vertical power spectral amplitude in the 40–100 Hz frequency range. The findings of this study provide new insights into the influence of adjacent bidirectional tunnels on environmental vibrations in suburban railway operations. These results are of significant importance for optimizing railway design and vibration mitigation measures.

Dynamic changes and influential factors of blowouts in a desert artificial ecosystem at the southeastern margin of Tengger Desert in China.

The wind-blown sand protection system in the Shapotou section of the Baotou-Lanzhou Railway is a representative artificial ecosystem in a desert region. Over the past 70 years, this system has transformed mobile dunes into fixed dunes through vegetation succession, relying solely on natural rainfall without additional irrigation. However, ecosystem sustainability has been endangered by the emergence of numerous blowouts. Therefore, understanding the status and developmental trends of these blowouts is crucial for maintaining the system and ensuring railway safety. In this study, we quantitatively analyzed the number, spatial pattern, and evolution process of blowouts using a landscape pattern index and Spatial-Temporal Analysis of Moving Polygons (STAMP) model with remote sensing images from 2009 to 2022. Currently, blowout areas account for 1.57% of the total area with a clustered distribution. The number of blowouts increased significantly from 308 to 463 between 2009 and 2022 and increased with increasing distance from the railway line. Various evolutionary events have occurred among the blowouts, with peak frequencies in the generation and disappearance events observed by 2022. The average growth rate of blowouts was 7.32% in areas with less than 40 years of sand fixation but less than 1% in areas with more than 40 years, and mid-sized blowouts predominated the overall protection system. There was little difference between the blowout wind-erosion area and the fixed area in the natural environment. However, human activities can accelerate the evolution of blowouts, leading to more frequent contraction and expansion events and significantly increasing the area of wind erosion.

Использование энергии рекуперации для обогрева стрелочных переводов от контактной сети постоянного тока с напряжением 3 кВ

Purpose: to create a system for the use of energy recovery on sections of railways electrified with direct current with a voltage of 3 kV. The proposed system should make it possible to use the energy of regenerative braking generated by an electric locomotive or a DC electric train for heating switches during regenerative braking and insufficient power of traction consumers or their absence in the traction network. Methods: analysis of statistical data on the modes of operation of electric rolling stock and traction network, execution of train schedules, analysis and synthesis of circuit solutions, study of domestic and foreign experience in the utilization of energy recovery in railway transport. Results: the principle of using energy recovery, which cannot be used due to the low load in the contact network, for heating switches, increasing the energy efficiency of transportation on electrified rail transport, is proposed. Practical significance: the possibility of using electric energy recovery of electric rolling stock for heating switches in winter is shown, if it is impossible to consume it by other electric locomotives and electric trains. This system can be used in areas electrified with direct current with freight and passenger traffic, which operates electric rolling stock (EPS) with regenerative and regenerative-rheostatic braking.

Snow Avalanche Hazards and Avalanche-Prone Area Mapping in Tibet

Snow avalanche is one of the major natural hazards in the mountain region, yet it has received less attention compared to other mountain hazards, such as landslides, floods, and droughts. After a comprehensive overview of snow avalanche hazards in Tibet area, the spatial distribution and main driving factors of snow avalanche hazards in the high mountain region in Tibet were presented in the study first. Snow avalanche-prone areas in Tibet were then mapped based on the snow cover distribution and DEM data and were validated against in situ observations. Results show that there are the highest frequencies of avalanche occurrences in the southeastern Nyainqentanglha Mountains and the southern slope of the Himalayas. In the interior of plateau, avalanche development is constrained due to less precipitation and much flatter terrain. The perennially snow avalanche-prone areas in Tibet account for 1.6% of the total area of the plateau, while it reaches 2.9% and 4.9% of the total area of Tibet in winter and spring, respectively. Snow avalanche hazards and fatalities appear to be increasing trends under global climate warming due to more human activities at higher altitudes. In addition to the continuous implementation of engineering prevention and control measures in pivotal regions in southeastern Tibet, such as in the Sichuan–Tibet highway and railway sections, enhancing monitoring, early warning, and forecasting services are crucial to prevent and mitigate avalanche hazards in the Tibetan high mountain regions, which has significant implications for other global high mountain areas.

Моделирование прохождения железнодорожного состава сеточно-характеристическим методом в условиях многолетних мерзлых грунтов цинхай-тибетской железной дороги

When designing a railway track in permafrost conditions, it is essential to select appropriate materials for constructing the subgrade and embankment. A notable example is the Qinghai-Tibet railway (QTR) section, where elastic parameters of the components making up the railway structure, subgrade, and layers of frozen soil are known. A grid-characteristic method is utilized to simulate the propagation of elastic waves from rail and sleeper fastening zones in the transverse cross-section of the railway. When solving the direct problem of numerical ultrasonic investigation of the railway track structure under variable ballast prism foundation from plain-fill soil to crushed rock, vector speed modulus and vertical load fields over time are obtained. Analysis of the results indicates the feasibility of using crushed rock as a foundation for embankments, consistent with findings from other researchers applying finite-element approaches.

Optimization of Curve Correction in the Plan Using Computer Modeling to Improve Train Safety

Purpose. The authors intend to develop and implement innovative approaches to optimizing curve correction in the plan of railway tracks using computer modeling. This process aims to: improve traffic safety; improve the smoothness of the ride, which increases passenger comfort; eliminate speed limits on curved sections, which reduces travel time and increases railroad capacity; reduce track maintenance and rolling stock repair costs. The use of special software to simulate various scenarios of train traffic along the adjusted curves will allow us to assess the impact of the train flow structure on the speed, rolling stock dynamics, and track condition. Methodology. The study is based on the theory of mathematical modeling and numerical calculation methods. To find the best option for the reconstruction of railway sections, the line is considered as a complex system consisting of various infrastructure facilities. Due to their unsatisfactory technical condition, these facilities may limit the speed of traffic on certain sections. The solution to this problem is complicated due to the interdependence of such objects: the reduction of travel time on a particular section is not linear, and obtaining accurate results requires traction calculations taking into account various options for eliminating speed limits. Findings. A calculation algorithm for optimizing long sections of the railway plan is proposed. The algorithm allows to take into account the desired direction of shifts in the curves, which greatly facilitates the optimization process. An example of calculations based on the proposed algorithm is given, which demonstrates the effectiveness of the approach. Originality. The scientific and applied problem of optimizing the process of adjusting railway curves in the plan has been solved. This helps to improve the safety and speed of trains through the introduction of the latest computer modeling methods. Practical value. The implementation of the proposed technology for optimizing the railway plan will significantly increase the speed and safety of train traffic, as well as increase the throughput capacity of railway lines. This will be an important step for the integration of Ukrainian railways into the European transportation system.

Biodiversity monitoring with intelligent sensors: An integrated pipeline for mitigating animal-vehicle collisions

Transports of people and goods contribute to the ongoing 6th mass extinction of species. They impact species viability by reducing the availability of suitable habitat, by limiting connectivity between suitable patches, and by increasing direct mortality due to collisions with vehicles. Not only does it represent a threat for some species conservation capabilities, but animal vehicle collisions (AVC) is also a threat for human safety and security in transport and has a massive cost for transport infrastructure (TI) managers and users. Using the opportunities offered by the increasing number of sensors embedded into TI and the development of their digital twins, we developed a framework aiming at managing AVC by mapping the collision risk between trains and ungulates (roe deer and wild boar) thanks to the deployment of a camera trap network. The proposed framework uses population dynamic simulations to identify collision hotspots and assist with the design of sensors deployment. Once sensors are deployed, the data collected, here photos, are processed through deep learning to detect and identify species at the TI vicinity. Then, the processed data are fed to an abundance model able to map species relative abundance around the TI as a proxy of the collision risk. We implement the framework on an actual section of railway in south-western France benefiting from a mitigation and monitoring strategy. The implementation thus highlighted the technical and fundamental requirements to effectively mainstream biodiversity concerns in the TI digital twins. This would contribute to the AVC management in autonomous vehicles thanks to connected TI.

Analysis of the efficiency of suburban passenger transportation on the Lviv railway sections

A developed transport system ensures the population's needs in safe movement and guarantees stable functioning and development of the production sphere. Despite being consistently unprofitable, suburban transportation by railway remains attractive for many population categories. The developed railway network, the low cost of transportation, and the capacity reserve of most sections partially compensate for the existing shortcomings and contribute to further development and open new prospects for attracting additional users of transport services. The main problems of suburban passenger transport, which worsen the quality of the services provided and affect the competitiveness of railway suburban transport compared to other modes of transport, are examined in this article. During the analysis of the schedule of suburban trains departing and arriving at the Lviv station, irrational management decisions were found that left room for improvement. In addition, the load factor of rolling stock on the routes Lviv-Sambir-Sianky and Sianky-Sambir-Lviv was determined, and it dropped to 40% during the follow-up, which indicates inefficient use of rolling stock. The ratio of the time the train stays at the stops to the total duration of the route in suburban traffic is also calculated. The time on the road for the Sambir- Stryi route was 69%, and the technical speed was only 21.7 km/h. The results obtained in the article are also typical for many other monitoring areas, indicating this problem's repeatability. The positive experience of European countries in solving similar problems allows us to react correctly to the situation and take short-term measures to change the dynamics to a positive one without additional time losses. It is also worth noting that a set of measures to improve the services provided to passengers must be carried out according to the requirements of the Technical Specifications for Interoperability, which must be ensured upon joining the European Union. Further investigations should analyze the flow of passengers at all stations and stopping points to identify the main points of creating passenger flow on researching routes.

Study on the mitigation effect and mechanism of solar heating subgrade system on frost heave of railway subgrade in cold regions

Frost heave represents a significant factor influencing the smoothness of railway track and the long-term service performance of subgrade in cold regions. The solar heating subgrade system (SHSS) represents a promising approach for mitigating subgrade frost heave. However, the mitigation effect and mechanism of SHSSs on subgrade frost heave remain unclear. In this paper, the mitigation effect and mechanism of SHSSs on subgrade frost heave were systematically analyzed by numerical simulation. Finally, the application effect of SHSSs combined with insulation materials in the subgrade of the Xining-Golmud section of Qinghai-Tibet Railway (QTR) was evaluated by field test. The numerical results demonstrate that the reduction in the freezing rate (by 85 %) and the freezing depth (by 95 %) of the heating subgrade, which results in a decrease of moisture migration and ice lenses formation, is the primary reason why SHSSs can make the frost heave less than the permissible frost heave value of 5 mm. The monitoring results in the subgrade of Xining-Golmud section of QTR also indicate that SHSSs combined with insulation materials can reduce frost heave from 22.5 mm to 5 mm, and significantly reduce the lateral differential deformation of subgrade.

Discrete control model Q-learning for an energy storage system with a hydrogen unit of an autonomous hybrid power plant of a railway substation

The paper considers the prospects for creating autonomous hybrid power plants using renewable energy sources and hydrogen as energy storage systems, as well as storage batteries, for the railway power supply system. A comparative analysis of various energy storage systems is carried out. A simulation model has been created that takes into account the characteristics of electric rolling stock trains, a model of the contact network of the inter-station zone of the railway stage, and a model of the energy storage system. Managing the flow of electricity in an autonomous hybrid power plant requires considering forecasts of electricity consumption and generation and the level of charge of the energy storage device. To solve the problem of synthesizing a control algorithm, the use of matrix Q-learning is proposed. The novelty of the study lies in the proposed approach of applying Q-learning to the problem under consideration based on discretization of input and output parameters of the model and verification of the approach on a simulation model built for a real railway section between the Yaya and Izhmorskaya stations (Kemerovo region of the Russian Federation). It is shown that the use of the proposed system makes it possible to equalize the voltage in the network between traction substations and provide a significant increase in the capacity of the railway section, and the proposed method of matrix Q-learning makes it possible to synthesize an effective algorithm for controlling the energy storage system as part of an autonomous hybrid power plant.

Land subsidence analysis using InSAR along the RiLan high-speed railway in Heze, China

The Heze section of the Rizhao-Lankao High-Speed Railway (RLHR-HZ) officially began operations in June 2021. Previous studies have shown that the RLHR-HZ crosses two subsidence zones. In this study, we analysed ground displacement along the RLHR-HZ using Sentinel-1A SAR data collected from June 2021 to June 2023, employing both Permanent Scatterer and Distributed Scatterer techniques. The results indicate a reduction in the displacement rate; however, subsidence continues along the RLHR-HZ, with displacement rates ranging from −16 mm/yr to −5 mm/yr. This reduction is likely due to the cessation of mining activities and the replenishment of groundwater.

A simple method for automatic recreation of railway horizontal alignments

This paper deals with the problem of recreating horizontal alignments of existing railway lines. The main objective is to propose a simple method for automatically obtaining optimized recreated alignments located as close as possible to an existing one. Based on a previously defined geometric model, two different constrained optimization problems are formulated. The first problem uses only the information provided by a set of points representing the track centerline while the second one also considers additional data about the existing alignment. The proposed methodology consists of a two-stage process in which both problems are solved consecutively using numerical techniques. The main results obtained applying this methodology are presented to show its performance and to prove its practical usefulness: an academic example used to compare with other methods, and a case study of a railway section located in Parga (Spain) in which the geometry of its horizontal alignment is successfully recovered.

СИСТЕМА АВТОМАТИЧЕСКОГО ПОСТРОЕНИЯ РЕГУЛИРОВОЧНЫХ ХАРАКТЕРИСТИК ПЕРЕГОНОВ ДЛЯ ЦЕНТРАЛИЗОВАННЫХ ИНТЕЛЛЕКТУАЛЬНЫХ СИСТЕМ УПРАВЛЕНИЯ ДВИЖЕНИЕМ ПОЕЗДОВ

the relevance of developing a system for automatic construction of regulating characteristics of railway sections for centralized train traffic control is discussed. Regulating characteristics allow determining the minimum permissible interval for train departure from the station, considering the given travel time of two consecutively moving trains and the specified dwell time of the leading train. The principles of constructing an automatic system for generating these characteristics are presented. Examples of the results of constructing adjustment characteristics for metro lines are provided.

Risk assessment of national railway infrastructure due to sea-level rise: an application of a methodological framework in Italian coastal railways

Nowadays, within the built environment, railway infrastructures play a key role to sustain national policies oriented toward promoting sustainable mobility. For this reason, national institutions and infrastructure managers need to increase their awareness in relation to the current and future climate risks on their representative systems. Among climate change impacts, preventing the effects of sea-level rise (SLR) on coastal railway infrastructures is a priority. The first step in the climate change adaptation policy cycle is the development of an ad hoc climate risk assessment. In this view, this research develops a vulnerability and a risk assessment metric to identify the hotspots within a national coastal railway due to the SLR impacts. The proposed methodology required different steps to quantify the SLR projections and the vulnerability characteristics of the assets, in terms of sensitivity and adaptive capacity. The investigated case study is the coastal railway infrastructure in Italy, thanks to an initial approach of co-design participative processes with the national Infrastructure Manager: Rete Ferroviaria Italiana (RFI). The results of this application, although not included in the paper due to confidential reasons imposed by the infrastructure manager — led to a clear identification of the areas and the coastal railway sections which are exposed to high levels of risks and of the places which require priority actions for urgent adaptation in a view of climate proof infrastructures.

Pantograph Slider Detection Architecture and Solution Based on Deep Learning.

Railway transportation has been integrated into people's lives. According to the "Notice on the release of the General Technical Specification of High-speed Railway Power Supply Safety Testing (6C System) System" issued by the National Railway Administration of China in 2012, it is required to install pantograph and slide monitoring devices in high-speed railway stations, station throats and the inlet and exit lines of high-speed railway sections, and it is required to detect the damage of the slider with high precision. It can be seen that the good condition of the pantograph slider is very important for the normal operation of the railway system. As a part of providing power for high-speed rail and subway, the pantograph must be paid attention to in railway transportation to ensure its integrity. The wear of the pantograph is mainly due to the contact power supply between the slide block and the long wire during high-speed operation, which inevitably produces scratches, resulting in depressions on the upper surface of the pantograph slide block. During long-term use, because the depression is too deep, there is a risk of fracture. Therefore, it is necessary to monitor the slider regularly and replace the slider with serious wear. At present, most of the traditional methods use automation technology or simple computer vision technology for detection, which is inefficient. Therefore, this paper introduces computer vision and deep learning technology into pantograph slide wear detection. Specifically, this paper mainly studies the wear detection of the pantograph slider based on deep learning and the main purpose is to improve the detection accuracy and improve the effect of segmentation. From a methodological perspective, this paper employs a linear array camera to enhance the quality of the data sets. Additionally, it integrates an attention mechanism to improve segmentation performance. Furthermore, this study introduces a novel image stitching method to address issues related to incomplete images, thereby providing a comprehensive solution.

A Performance Evaluation Method for Long and Steep Uphill Sections of Heavy-Haul Railway Lines

Any system for evaluating the safety service performance of heavy-haul railway lines must effectively reflect the real-time service status of the line. The working conditions of heavy-load lines are complex and diverse, particularly on uphill sections. Existing evaluation systems struggle to accurately reflect the service conditions of long and steep uphill sections bearing heavy loads, posing a significant threat to the safe operation of these lines. To address this problem, we propose a new method for evaluating the safety service performance of long and steep uphill sections of heavy-haul railway lines by establishing a scoring system based on the Analytic Hierarchy Process (AHP). First, damage indicators for heavy-haul lines are categorized into three groups: track geometry status indicators, track structure status indicators, and track traffic status indicators. Using data from existing heavy-haul lines and maintenance experiences, we determine a score deduction standard, classifying lines into four levels based on their safety service quality. Next, we establish a coefficient table for the service performance of long and steep uphill sections after the corresponding scores are deducted. Using data for the length and elevation grade of the actual uphill section, we adjust the deducted scores of the track structure status indicators, enhancing the evaluation system’s accuracy in describing the working conditions. Finally, we verify the stability of the entire system by conducting a sensitivity analysis of the indicator evaluation results using the One-At-a-Time (OAT) method. This method fills a critical gap in the safe operation and maintenance of heavy-haul railways and provides a safety guarantee for the operation of long uphill sections of heavy-haul railways.

A self-satisfying cooling system based on cold energy storage for the locomotive in a high geothermal tunnel

Effective thermal management of locomotive systems is crucial for ensuring the safe operation of trains through high geothermal tunnels. By taking advantage of the frequent alternation of high-temperature tunnels and cold climate environment, a self-satisfying cooling system based on cold energy storage is proposed, in which a phase change heat exchanger between air and phase change material (succinic acid with 20 wt% expanded graphite) is developed to store cold energy outside tunnels and improve air-cooling efficiency inside tunnels. Numerical models are established to examine the thermal environment in a typical tunnel and the effectiveness of the proposed cooling system. The results indicate that because of the heat exhausted from the train and the thermal dissipation from the surrounding hot rock, the air temperature in the tunnel can rise above 50 °C. The proposed cooling system can release the cold energy from phase change material to keep the air outlet temperature below 40 °C, increasing the energy efficiency and reliability of locomotive operation. By examining the effects of locomotive operating conditions and orthogonal analysis of multi-factors, the heat exchanger structure and other operating conditions are recommended for the self-satisfying cooling system. Finally, the cooling system’s effectiveness is confirmed for the full-line operation of the locomotive along the Ya’an-Nyingchi section of the Sichuan-Tibet Railway in both summer and winter climatic conditions. This study is significant because it provides a novel design scheme for locomotive’s thermal management in high geothermal tunnels and other similar engineering conditions with natural cold sources.

Effectiveness analysis of anti-galloping of spacer for catenary additional wires in strong wind section of high-speed railways

Effectiveness analysis of anti-galloping of spacer for catenary additional wires in strong wind section of high-speed railways

Modeling of energy recovery processes in railway traction power supply systems

Regenerative braking of trains can provide significant energy saving and a sizeable reduction in greenhouse gas emissions. The efficiency of energy recovery can be defined using an efficiency indicator equal to the product of the free-fall acceleration and the fraction of potential energy used in the recovery. Its slope dependence is well approximated by a polynomial of the third degree. The operating conditions of the traction power supply system of the mountain pass section of the main railway were modeled. The results obtained allowed the following conclusions to arrive at: regenerative braking is accompanied by circulating currents in adjacent inter-substation areas and leads to an absolute and relative increase in electrical energy losses in the traction network; the share of active energy losses rises by several times; the energy recovery causes a change in the direction of active energy flows at traction substations with a steep increase in reactive power consumption by trains; the energy recovery produces a significant decrease in voltage on the current collectors of electric locomotives; the voltage on the section under consideration, with three trains weighing tons decreased to 23 kV due to the large reactive energy consumption. © 2024 The Authors. Published by Elsevier Ltd.

Research on intelligent identification and resource utilization of TBM muck in breezy granite strata

Tunnel boring machines (TBMs) excavating breezed granite strata produce a lot of muck, including rock powder and gravel. To promote waste recycling and environmentally friendly muck utilization, a series of studies was conducted on the intercity railway section from ShenZhen Airport East Station to HuangMaBu Station in China. First, the muck image dataset was obtained using a camera, and the SAM-YOLO neural network model was adopted to intelligently identify the features of the particle size and content of the muck. Subsequently, the muck was used as an alternative material for the backfill slurry raw material, and the optimal slurry ratio was determined through laboratory tests. Finally, a new backfill slurry was applied on-site. The results demonstrated that the established SAM-YOLO model can accurately and quickly identify muck characteristics, which can be roughly classified by particle size into three categories: rock powder (0-5 mm), gravel (5-10 mm), and crushed rock (10-31.5 mm). Rock powder was utilized to make the monomortar, gravel was used for backfilling, and the crushed rock was broken again to gravel particle size to be used for backfilling. The laboratory test and field application results indicated that the new monomortar can fulfil engineering requirements after the backfilling of gravel, and the optimal water, cement, and rock powder mix ratio is 0.9:1.0:1.0. This research thus provides effective guidance for the utilization of muck in similar projects.