Railway Line Research Articles

Into the circle. Animal and human deposits in a new Upper Guadalquivir site from the beginning of the 3rd millennium Cal BC (Grañena Baja, Jaén)

In 2014 due to the projected layout of the Madrid – Jaén high-speed railway line, a preventive archaeological intervention was carried out on a hill near the Guadalbullón riverbed within the farmland of Grañena Baja (Jaén). During the work, a multi-sequential Late Prehistory occupation, starting from the mid-5th millennium and reaching the end of the 3rd millennium, was documented. The phase corresponding to the last quarter of the 4th and the beginning of the 3rd millennium Cal BC stands out for the presence of circular features containing complete or partial human and domestic animal skeletal remains, in some cases, clearly related. The isotopic values of human collagen are relatively homogeneous (?15N = 9.0 ± 0.6; ?13C = -18.9 ± 0.4) and consistent with a diet based on proteins of animal origin.

An Automatic Train Operation Based Real-Time Rescheduling Model for High-Speed Railway

With the continuous development of the Automatic Train Operation (ATO) system in high-speed railways, automatic driving is progressively supplanting manual operations, ushering in a new era of predictability and reliability for high-speed railway transport. Concurrently, the advent of the ATO system provides a notable impact on real-time rescheduling during disruptions, as it equips dispatchers with precise insights into train operation statuses. This paper is dedicated to a thorough analysis of how the transition to automatic driving in train operations influences the real-time rescheduling model. Based on the distinctive impact of the ATO system on real-time rescheduling, we have proposed a mixed-integer linear programming model that combines train re-timing, reordering, and the minimization of passenger delays. To validate the effectiveness of our model, we present several experiments conducted using data from the Beijing–Shanghai high-speed railway line. The results unequivocally demonstrate that our ATO-based model significantly mitigates train delay time, demonstrating its practical value in optimizing high-speed railway operations.

Exploring the impact of transportation on heavy metal pollution: A comparative study of trains and cars

This study aimed to investigate the impact of road and rail traffic on the soil through the analysis of the presence of heavy metals in soil samples collected next to a busy highway, local roads, and next to an active railway line. Results showed that cars emitted higher levels of heavy metals than trains. Soil samples near the highway had higher levels of Cu, Ni, and Hg. The values of the calculated indices like geo-accumulation index, potential toxicity response index, ecological risk factor, contamination factor, pollution load index, Nemerow's pollution index, and degree of contamination confirm that the soil samples sampled near the highway are the most polluted and highway have the greatest negative impact on the soil environment. These results suggest that controlling car emissions through strict regulations and promoting public transportation could effectively reduce the heavy metal concentrations in soil, particularly from highway emissions.

Influence of train-generated vibrations on embankment

Roads and railway lines are often constructed on different geotechnical structures such as tunnels, cuttings, and/or embankments. Three main parts are necessary to consider to evaluate vibration: the source of vibrations, vibration propagation path, and receiver of the signal. This paper describes a review of the influence of train-generated vibrations on an embankment and a building in the surroundings. The first presented case study documents an interpretation of seismic signal in the frequency domain using wavelet transform. The algorithm, which we apply to the computation of the wavelet transform of the velocity component record, is based on the pyramidal algorithm, and the result of this procedure is used for an interpretation of data. The discrete wavelet transform was applied to the construction of a 3-dimension mapping of the time-frequency decomposition. An example of the numerical model on the FEM method (the MIDAS GTS software) shows the vertical displacement of the embankment body during the movement of a train. The creation of these models is strictly based on the results of experimental seismological measurements. Then, the source of vibration is represented by a typical train/vehicle that runs on the nearest part of the railway/road at the most efficient velocity.

Prediction of departure delays at original stations using deep learning approaches: A combination of route conflicts and rolling stock connections

Rolling stock connections and route conflicts of trains at terminal stations are critical to train delay propagation and prediction on the railway networks. Previous studies primarily focused on delay prediction/propagation from a macro perspective, without considering the two factors. To address this problem, a hybrid neural network architecture, called TLF-net, is proposed to predict departure delays at original stations (DDOSs), considering the rolling-stock connection and potential route conflicts in the railway network. TLF-net consists of a transformer, a long short-term memory (LSTM), and a fully-connected neural network (FCNN) block, to separately address variables with different characteristics. Based on the real-world data from two terminal stations in China, the experimental results show that the consideration of the potential route conflicts from the network can considerably improve TLF-net's prediction performance over the model that only considering train interactions on a single railway line. Also, it is proven that arrival/departure routes of consecutive trains are crucial for delay prediction, while using the transformer block can efficiently reveal the route conflict severity between arrival/departure routes. The sensitivity analysis to influence factors demonstrates the significance of considering the rolling stock connection and potential route conflicts. Finally, to support real-time railway traffic management, a train arrival delay prediction model from our previous study is integrated to predict the input of TLF-net (i.e., train arrival delays), enabling the proposed model to dynamically predict the DDOSs. This dynamic updating lengthens the prediction horizon (the prediction time ahead), making it better support real-time train traffic control and management.

Dynamic hybrid observer-based early slipping fault detection for high-speed train wheelsets

Early slipping fault detection of High-speed Train (HST) wheelsets on ramped railway lines has been a challenging problem due to the difficulty of achieving accurate detection in a limited time-frame. A dynamic hybrid observer-based early slipping fault detection strategy is proposed. Firstly, a hybrid observer-based adhesion coefficient estimation method is proposed. The hybrid observer is constructed in an interconnected configuration, which integrates the estimated ramped line angle into the adhesion coefficient estimation. Then, a multivariate evaluation function (MEF)-based parameter dynamic adjustment method is proposed. The MEF is constructed to reconcile the trade-off of the speediness and smoothness of the hybrid observer. Finally, a dynamic adhesion coefficient-based early slipping fault detection method for HST wheelsets is proposed. And the proposed strategy is verified on the hardware-in-the-loop(HIL)-based platform. The test results show that the proposed strategy can actualize millisecond-level early slipping fault detection and reduce the false detection rate on ramped railway lines.

Comparison of the Structural Performance of Ballasted and Non-Ballasted Pavement of the Railway with the Help of Beam Models on Elastic Bed and Finite Element Model

Today, many countries are opting for ballast less paving of railways using concrete line slabs as an alternative. Ballast paving is particularly prevalent in high-speed lines, urban railways, as well as bridges and tunnels designed for high loads and speeds. The priority lies in ensuring that these lines are paved with proper structural performance, especially considering the mechanics of the line and the choice between ballast pavement and line slabs. This article delves into the structural modeling and analysis process of ballast and slabs for railway lines. Models for both ballast and slab lines under passage have been developed. The study investigates the train wheel load and the impact of bed conditions. Theoretical solutions, including the beam model on an elastic bed for ballast lines and the two-beam model for line slabs, have been presented. Multiple finite element models were explored using ABAQUS software, confirming the accuracy of the theoretical results with acceptable precision. This work establishes a suitable model for calculating the effects of vertical force on the line pavement structure and provides applications for comparing design performance between ballast and slab lines. The results highlight the optimal performance of the modeling and the superiority of the line slabs.

Railway track monitoring using drones

In recent times, the use of drones to monitor various types of transportation lines has attracted more attention. Unmanned aerial vehicles (UAVs) have a number of potential benefits over manual methods for inspecting transportation lines due to its permit scalable, quick, and affordable solutions to tasks that would otherwise be unsuitable for individuals who are subject to fatigue and measurement uncertainty. Therefore, the current study investigates the use of drones in image processing, early warning and situation assessment in the transportation sector. Due to their ability to capture aerial images in extremely high resolution at a low cost and while also covering large areas, drones are a very important source of visual data. The main goal of this work is to collect and analyse drone-shot images using MATLAB software in order to locate the line’s fault and take the necessary corrective action to prevent accidents and save lives. The results of the current work concluded that the using of aerial image processing is very effective to increase and maximize the capacities of the transportation lines. Moreover, it gives more safety for the lines. UAV can survey and take pictures of the railway line for a distance of about 8.4 km in one hour, whereas a worker would need a full day to cover the same distance (a worker scans a distance of 7 km per day), so it saved time and effort.

Review Of Risk Identification Of Pipeline Buried Under Railroad Tracks

The presence of pipes beneath railway lines poses potential risks and hazards to railway operations. Identification of the risks arising from pipes located under railway lines is necessary for evaluation and preparation of strategic measures to reduce the level of risk. Risks to be aware of include pipe deformation, corrosion, design and installation errors, and operating errors. To ensure safety, pipe monitoring and inspection must be conducted regularly. Pipe inspection also needs to consider geotechnical elements to ensure that railway infrastructure remains safe for operation. This paper reviews several published studies and standards related to the safety of pipelines under the railways and summarizes the potential failures of pipelines located beneath railway tracks, various aspect of pipelines and railway safety, and the standards that can be used as references in designing pipelines buried beneath railway tracks

Could the Southern-Kurtalan Express be as Popular as the Eastern Express? Comparative SWOT Analysis

Train tourism can play a critical role in the development of the tourism potential of the cities, such as increasing the tourism potential of the cities, economic contribution, reducing the differences in the level of development between regions, and employment in the cities where the railway line passes, and thus in the development of the country’s tourism potential. This situation occurred in the cities of the route where the Eastern Express passed. Therefore, the aim of this research is to present a comparative SWOT framework on whether the Southern-Kurtalan Express has the potential to be popular like the Eastern Express, and to explore the perception and behavioral tendencies of travelers towards the Southern-Kurtalan Express. While conducting interviews with 30 participants to create a SWOT matrix for the Southern-Kurtalan Express, the SWOT matrix for the Eastern Express was compiled from the relevant literature. Comparing the data from the participants and the SWOT matrices compiled from the literature, it can be deduced that the Southern-Kurtalan Express is as strong as the Eastern Express and even has more advantages but has similar weaknesses and that the Southern-Kurtalan Express faces significant opportunities as well as similarly wider threats. In this regard, the Southern-Kurtalan Express has a high potential to be as popular as the Eastern Express, but success can be achieved if all stakeholders act together to determine strategies for reducing the threat width and improving the potential.

The strengthening of the 130-year-old San Michele bridge in Paderno d’Adda, Italy – an experience between past and present

The San Michele Bridge in Paderno, Italy, is a prime example of the refurbishment of a historic structure. An architectural and historical landmark, it is the last of a remarkable group of trussed arch bridges built in the late XIX century to be fully operational, and serves the Seregno-Bergamo railway line and the provincial road SP54/166 connecting Paderno d‘Adda and Calusco. In 2014, after 130 years of service, the bridge was subjected to an extensive survey and inspection campaign to acquire a more profound knowledge of the structure and its reliability. Overall, the inspections revealed that the bridge was still in a decent state but needed refurbishment. This article will briefly present the challenges faced in the design and execution of the refurbishment works.

Differences among Four Quadrant Urban Areas around Stations Divided by Intersecting Railroad Lines

Differences among Four Quadrant Urban Areas around Stations Divided by Intersecting Railroad Lines

Failure Mode Analysis and Maintenance of Railway Overhead Line Rigid Stainless Steel Droppers and Multi-Strand Copper Jumpers

Droppers and jumpers are important components of railway overhead line electrification. Their effective maintenance is critical for the railway’s safe and reliable operation; the consequences of their failure can be disproportionally serious. This paper systematically analyses the components’ failure by applying the method of failure modes and effects analysis to the maintenance records and incident statistics of Britain’s East Coast Main Line. The analysis is presented with photographic evidence and a review of the current maintenance strategy and practice that addresses the risk of failure. These results can support improved dropper and jumper design and the development of more effective maintenance strategies to further prevent failure and operational disruption.

Integrated Planning for Depot Location and Line Planning Problems in the Intercity Railway Network with Passenger Demand Uncertainty

In this study, we present a mathematical model and solution approach for addressing the robust integrated intercity railway depot location and line planning problem (RIDLLPP), which encompasses the initial two stages of the railway planning process. Our primary objective is to identify depot locations that exhibit robustness across a range of likely future scenarios, and this is achieved by incorporating line planning decisions. The model focuses on five critical strategic determinations, namely the depot location, depot storage capacity, line operation, passenger assignment, and fleet allocation. To tackle this complex problem, we propose an iterative solution framework that combines the Differential Evolution (DE) algorithm with improved rounding heuristics (DE-IRH). To evaluate the effectiveness of our framework, we conduct a comparative analysis with the Gurobi solver using multiple medium-sized artificial instances. The results demonstrate that our proposed framework achieves an optimality gap of 4.87% while requiring less computational time. Furthermore, we validate the robustness of the model’s location choices across various input scenarios, thereby providing valuable insights for transportation planning agencies and railway companies that can inform their decision-making processes.

Nexuses between carbon emissions, trade openness, transport services, globalization index, and growth in China: targeting the sustainable development goals.

Since the end of the twentieth century, the world has observed a considerable upsurge in carbon emissions as several countries have surfaced as industrial centers and production monsters worldwide. The present study contributes to the existing literature examining the effects of carbon-based emissions, industrial value added, trade openness, transport services, railway lines, and globalization index on per capita GDP growth in China. The study covers a period of 40 years, from 1982 to 2021, introducing the impact of railway transport on GDP growth in contemporary environmental empirics. A vector error correction model (VECM) was applied to achieve the study's envisaged objectives. The findings of this study reveal that carbon emissions are responsible for the reduction of per capita GDP growth in China. On the contrary, industrial value added, transport services, railway lines, and globalization index positively support the per capita GDP growth-dependent variable. The study proposes that pragmatic policies are needed to control pollution resulting from carbon emissions. The eventual effect of maintaining greenhouse gases is expected to assist in achieving sustainable growth of per capita GDP leading to the accomplishment of sustainable development goals in the economy.

The optimal solution to the energy-efficient train control in a multi-trains system–Part 2: the optimality and the uniqueness

When a train travels in a multi-trains system, the power flow of other trains and the track grades make up the spatial–temporal area (STA) for the train. Finding the optimal solution for the energy-efficient train control (EETC) problem in STA can help reduce the net energy consumption. This paper studies the analytic method to obtain the optimal solution. In Part 1, the algorithm for the problem was designed. The underlying structure of the algorithm is the connection between three optimal states through optimal feasible strategy. In Part 2, the optimality of the optimal feasible strategy is verified through a generalised local energy functional, and its uniqueness is proved based on the variational method. Additionally, we discuss the influence of external power on the optimal solution of the classical EETC problem. Case studies using data for a real freight railway line are given to illustrate our results.

Analysis of Train-Track-Bridge Coupling Vibration Characteristics for Heavy-Haul Railway Based on Virtual Work Principle.

This paper introduces an innovative model for heavy-haul train-track-bridge interaction, utilizing a coupling matrix representation based on the virtual work principle. This model establishes the relationship between the wheel-rail contact surface and the bridge-rail interface concerning internal forces and geometric constraints. In this coupled system's motion equation, the degrees of freedom (DOFs) of the wheelsets in a heavy-haul train lacking primary suspension are interdependent. Additionally, the vertical and nodding DOFs of the bogie frame are linked with the rail element. A practical application, a Yellow River Bridge with a heavy-haul railway line, is used to examine the accuracy of the proposed model with regard to discrepancy between the simulated and measured displacement ranging from 1% to 11%. A comprehensive parametric analysis is conducted, exploring the impacts of track irregularities of varying wavelengths, axle load lifting, and the degradation of bridge stiffness and damping on the dynamic responses of the coupled system. The results reveal that the bridge's dynamic responses are particularly sensitive to track irregularities within the wavelength range of 1 to 20 m, especially those within 1 to 10 m. The vertical displacement of the bridge demonstrates a nearly linear increase with heavier axle loads of the heavy-haul trains and the reduction in bridge stiffness. However, there is no significant rise in vertical acceleration under these conditions.

The optimal solution to the energy-efficient train control in a multi-trains system-part 1: the algorithm design

When a train travels in a multi-trains system, the power flow of other trains and the track grades make up the spatial–temporal area (STA) for the train. Finding the optimal solution for the energy-efficient train control problem in STA can help reduce the net energy consumption. This paper studies the analytic method to obtain the optimal solution. In Part 1, we propose an algorithm specifically designed for this problem. The underlying structure of the algorithm is the connection between three optimal states through the optimal feasible strategy. We propose an algebraic method to calculate the optimal feasible strategy and discuss how it intersects with the speed limit. In Part 2, we will discuss the optimality and uniqueness of the optimal feasible strategy. Case studies using data from a real freight railway line are given to demonstrate the effectiveness of the proposed algorithm.

Multi-Objective Optimization for High-Speed Railway Network Based on “Demand–Supply–Management” Model

This paper develops a multi-objective optimization model for national high-speed railway network planning. Three objectives are proposed from the macro, meso, and micro perspectives, and these three objectives are considered simultaneously. Using real data, case studies are conducted to optimize China’s “four east–west and four north–south railway lines” network, which includes Beijing, Shanghai, Wuhan, Guangzhou, and Zhengzhou as main hubs. The results show that, on the one hand, the optimization model reduces the overlap between long-distance passengers and short-distance passengers on the high-speed railway line, facilitates the travel of passengers, and improves the line service capability; on the other hand, optimization of the network shortens the travel time of the passengers, reduces the cost of the railway, and improves the operation efficiency of the high-speed railway line network. The results show that the total travel time of all high-speed railway passengers in the optimization model is reduced by 18.4%, while the benefit rate of the operator increased by 21.99%.

An Integrated Method for Reducing Arrival Interval by Optimizing Train Operation and Route Setting

The arrival interval at high-speed railway stations is one of the key factors that restrict the improvement of the train following intervals. In the process of practical railway operation, sudden conflicts occur sometimes. Especially when the conflict arises at the station, because the home signal cannot be opened in time, the emergency may affect the adjustment of the train operation under the scheduled timetable, resulting in a longer train following interval or even delay. With the development of artificial intelligence and the deep integration of big data, the architecture of train operation control and dispatch integration is gradually improving from the theoretical point. Based on this and inspired by the Green Wave policy, we propose an integrated operation method that reduces the arrival interval by avoiding unnecessary stops in front of the home signal and increasing the running speed of trains through the throat area. It is a two-step optimization method combining both intelligent optimization and mathematical–theoretical analysis algorithms. In the first step, the recommended approaching speed and position are obtained by analytical calculation. In the second step, the speed profile from the current position to the position corresponding to the recommended approaching speed is optimized by intelligent optimization algorithms. Finally, the integrated method is verified through the analysis of two distinct case studies. The first case study utilizes data from the Beijing–Shanghai high-speed railway line, while the second one is based on the field test. The numerical result shows that the proposed method could save the entry running time effectively, compared with the normal strategy given by the train driver. The method can mitigate controllable conflict events occurring at the station and provides theoretical support for practical operation.