Freight Trains Research Articles

Using Passing Trains as Seismic Sources for Refraction Microtremor Site Characterisation Surveys: Rugeley, Staffordshire, UK

Microtremor seismic surveys are routinely used to provide shear wave velocities that are converted to soil stiffness site profiles. In this paper, we look to assess the feasibility of using trains as seismic sources to characterize near-surface geology, define the optimum survey parameters to collect train-induced vibrations (i.e., array location and orientation to the railway) and find how the geology affects train-induced vibration characteristics. Three-component train-induced shear wave vibrations were recorded on short (44 m) and long (115 m) linear seismic arrays, both parallel and orthogonal to the nearby railway embankment, using standard seismic refraction recording equipment. The collected data were divided into short/long array size/orientation and seismic components for each survey configuration. 1D shear wave velocity-depth profiles were also generated for all data sets. Results showed thst long linear arrays with vertical components, parallel to the railway embankment, was optimal with the greater depth ranges. The vertical component amplitude of train-induced vibrations was found to be affected by the site geology, increasing with the thickening of Quaternary deposits and having different magnitudes for trains traveling in different directions. Results showed that different apparent shear-wave velocities were obtained from different train groups and different seismic components. The passenger trains (i.e. Virgin Trains Pendolino and British Midland 319 series) generate Rayleigh waves at higher frequencies than the freight trains.

Effects of varying normal loads on the rail rolling contact fatigue behavior under various frequencies and creepages

Track irregularities caused by wheel and rail damage would lead to vibration at wheel-rail contact interfaces, resulting in the fluctuation of normal forces which would further increase the damage to both wheels and rails under operational freight train services. This study aims to investigate effects of varying normal loads on the rolling contact fatigue (RCF) behavior of rails under various creepages and vibration frequencies using a twin-disc test machine. Results indicated that tangential forces and wear rates both increased with the increase in creepages, while they decreased with the increase in vibration frequencies. In addition, surface and subsurface damage parameters, and characteristics of cracks in the railhead including average lengths, depths and angles first increased and then decreased with the increase in creepages, and they all decreased with the increase in vibration frequencies. Further, the sizes of wear debris particles decreased with the increase in both creepages and frequencies.

Efficient Deployment of Dual Locomotives in Regional Freight Rail Transport

The present article focuses on the efficient deployment of dual locomotives in regional rail freight transport considering the quantification of traction energy and energy savings. In the first part of the article, a categorization of dual locomotives, according to their power output in electric and alternative traction (and ratio of both power outputs) is proposed. The potential of deployment of chosen dual locomotives in Central European conditions (a sub-network of Czech railway network around mainlines electrified with AC) is verified by calculation of traction energy consumption of the model train (with two examples of dual locomotives). In addition to non-stop running through the entire line, traction energy consumption of stop (and following acceleration) in each intermediate station is calculated, for a particular direction. Then, appropriate freight train paths for passing passenger trains and saving of traction energy are proposed. The results are supplemented by sensitivity analysis in the form of calculation of traction energy consumption with variable numbers of loaded wagons, with the help of iPLAN/FBS timetabling software. The limitations are the maximum length or gross mass of the train. Finally, the conclusions obtained from the computational examples are evaluated and recommendations for appropriate deployment of dual locomotives and planning of targeted improvements of infrastructure are formulated.

Analysis of coupling system failures on freight trains

This paper presents an analysis of train coupling failure that led to trains break apart on the Serbian Railways over 10 years period. Train coupling failure of freight trains with single locomotives was considered. The analysis was done based on accident data combine with FMECA risk assessment. As a result distribution of failure along the train, driving regime and velocity were obtained, as well as the frequency of failure concerning the length and mass of the trains, load status, etc. The systematization of coupling failure helped to establish conditions leading to failure and to define the parameters causing it. Risk factors for coupling failure were determined using FMECA risk assessment. Preventive measures are recommended for the revision of maintenance. Risk analysis of coupling system failure can be different depending on the time of analysis (regulations, exploitation conditions) and the applied maintenance practice. FMECA analysis applied to train coupling systems based on regulation shows different permissible risk values that don't match exploitation data.

The influence of AAR coupler features on estimation of in-train forces

Inadequate management of large in-train forces transferred through coupler systems of a railway train leads to running and structural failures of vehicles. Understanding these phenomena and their mitigation requires accurate estimation of relative motions and in-train forces between vehicle bodies. Previous numerical studies have ignored inertia of coupling elements and the impacts between couplers. Thus, existing models underestimate the additional dynamic variations in in-train forces. Detailed multi-body dynamic models of two AAR (Association of American Railroads) coupler systems used in passenger and freight trains are developed, incorporating coupler inertia and various slacks. Due to the modeling and simulation complexities involved in a full train model, with such details of coupler system, actual longitudinal train dynamics is not studied. A system comprising only two coupling units, inter-connecting two consecutive vehicles, is modeled. Considered system has been fixed at one end and an excitation force is applied at the other end, to mimic a relative force transmission through combined coupler system. Simulation results obtained from this representative system show that, noticeable influence in in-train forces are expected due to the combined effect of inertia of couplers and intermittent impacts between couplers in the slack regime. Maximum amplitude of longitudinal reaction force, transferred from draft gear housing to vehicle body, is expected to be significantly higher than that predicted using existing models of coupler system. It is also observed that the couplers and knuckles are subjected to significant longitudinal and lateral contact forces, due to the intermittent impacts between couplers. Thus, accurate estimation of draft gear reaction force and impact forces between couplers are essential to design vehicle and coupler components, respectively.

The LBJ School Experience

I hope that the future public servants who begin their careers in the School will tomorrow be serving effectively not only in the bureaus and departments of the Federal Government and the Congress but also in city halls and court houses and state capitols—not only in Texas but in every region in the country. Above all, I hope that as they master new techniques and disciplines to improve the machinery of government, they will still build their careers of service around a dedication to one of the most cherished principles of our democracy: the greatest good for the greatest number (Lyndon B. Johnson, May 22, 1971). Given high standards of living and modern medicine, there seems to be no inherent limit to how long humans can live. In the United States, the population is rapidly aging, and life expectancy has reached historical highs. By 2040, 20% of individuals will be 65 or older (The Administration on Aging, 2021). Those who reach 65 could live more than 20 years longer (Kochanek et al., 2020). If current trends continue and existing policies and programs are unchanged, the Social Security Trust Fund will be depleted by 2034 (Social Security Administration, 2022); Medicare’s trust fund will go broke by 2028 (Centers for Medicare and Medicaid Boards of Trustees, 2022); and Medicaid’s funding for long-term care for low-income older adults will consume an ever-increasing portion of state budgets (The Commonwealth Fund, 2020). To make matters worse, a lack of personal savings among working-age Americans means that many will be unable to finance their own retirement (Angel, 2018a). Despite early warning signs, these obligations represent a fiscal freight train that is bearing down on families and the state.

Effect of Wheel Polygonization on Vehicle-Track Coupling System with Different Track Structures

Wheel polygonal wear aggravates the dynamic responses of vehicle-track coupling systems, especially for the wheel-rail interaction force and rail vibration acceleration, which will influence train operation safety. Previous studies about wheel polygonal wear mostly focused on high-speed trains, while freight trains and track systems are rarely involved. This paper presents a comprehensive investigation of the wheel polygonization effect on the dynamic responses of vehicle-track coupling systems, involving a high-speed train, a heavy haul freight train, ballasted tracks, and slab ballastless tracks. With the combined excitation of track irregularity and wheel polygons of different orders and wave depths, the simulation results are analyzed in the time domain and frequency domain, and this indicates that the rail accelerations and wheel/rail forces of slab tracks induced by over-15th order polygonal wear are more intense than those of ballasted tracks as high-speed trains pass at speeds of 300 km/h and above, and the responses of freight trains are more severe than those of passenger trains on ballasted tracks. For the vehicle system of freight wagons, wheel polygonization has a more obvious effect on the wheelset than the car-body and bogie frame. Moreover, rail vertical acceleration is more sensitive to the various types of wheel polygonal defect in different track structures, and this can serve as a vital indicator of polygonal wear.

Research on Information Fusion Preview Control for Freight Train Speed Tracking

Background: With the increase in the speed and capacity of freight trains, the safety, energy efficiency and intelligent operation of train operation have become increasingly important. Automatic freight trains operation can replace manual operation with automated control systems, which can guarantee the safety of train operation, and improve operational efficiency and reduce operational energy consumption. Objective: Solve the problem of tracking accuracy and stability deterioration caused by multi-information of freight train. Methods: Global navigation satellite system, inertial navigation system and speed measuring motor are selected to construct a speed fusion measurement model by using loosely coupled integrated navigation and improved entropy weight method. Calculate the information quantity of performance index and control quantity in preview control, get the controlled quantity of information fusion optimal preview control. Results: The average tracking error of the multi-source information fusion preview controller is 0.038m/s, which is 49% lower than that of the control experiment. Conclusion: Multi-source information fusion preview controller can effectively reduce the tracking error of freight train speed tracking system and improve the accuracy of automatic freight trains operation.

Verification of Railways Noise Mapping Using CNOSSOS-EU: Case Study on Freight Trains

Freight trains are a relevant source of environmental noise and require an acoustical assessment to quantify the exposure of the population using noise mapping. Once the results of the noise calculations have been developed, it might be necessary to adopt mitigation strategies that can be validated using these noise models. It is becoming increasingly common to undertake some form of validation exercise to cross-reference the calculated levels with measurements to reduce the uncertainty in the action planning. Based upon the results of the monitoring, the measured data may then be stratified regarding the source data and meteorological data and introduced into the calculation model, to enable the model to replicate the situation during the measurement windows (meta-models). The results from the calculations of each of these meta-models may then be compared with the noise measurement results as the basis for the validation study. This paper presents an overview of a verification project undertaken in South America where such a process was followed using the CNOSSOS-EU as the basis of comparison.

Effective ways to compare two families of freight trains

The paper shows several use cases of the “relative approach” method, envisaged by international recommendations, for evaluating the safety of two families of freight trains. This is relevant when a decision is needed about a new technology or a new operating mode of freight trains to keep the same safety as existing trains. The paper discusses the heterogeneity of the database of trains and provides examples of the classic application of the “relative approach”, highlighting the effect of train operation. Furthermore, it shows the application to DAC and radio-controlled Traction Units. Finally, it introduces the “Iterative Proportional” algorithm to generate a freight train from an existing one just by changing the hauled mass of each wagon. This algorithm is helpful when the “relative approach” is applied to trainsets having articulated wagons and running with a similar braking regime.

DETERMINING THE NEED FOR TRAIN LOCOMOTIVES IN THE CONDITIONS OF TRAINE MOVEMENT IMPAIRMENT

This article presents the methods of determining the need for train locomotives in conditions of imbalance of train traffic. To check the reliability of the obtained results, as an example, the indicators of use of electric locomotives for the AV circulation section were analyzed. Also, an algorithm for determining the fleet of electric locomotives needed to service freight trains has been developed

Investigation of Stress Distribution in a Railway Embankment Reinforced By Geogrid Based Weak Soil Formation Using Hybrid Rnn-Eho

As the primary method of track support, traditional sloping embankments are typically used by railroad lines. Geosynthetically Reinforced Soil (GRS) systems, as an alternative to traditional embankments, have gained appeal, notably for high-speed lines in India. This system's reduced base area compared to traditional embankments means that less ground stabilization, improvement, and land taking is necessary. The research's findings provide intriguing strategies that may be implemented into the way tracks are designed now to accommodate faster freight trains pulling greater loads. This research explains how to anticipate the bearing capacity of weak sand supported by a method of compacted granular fill over natural clay soil using a hybrid Recurrent Neural Network (RNN) and Elephant Herding Optimization (EHO) with Georgic reinforced soil foundation. The exact prediction target for the proposed model was developed by using displacement amplitude as an output index. A number of elements influencing the foundation bed's properties, Georgic reinforcement, and dynamic excitation have been taken into account as input variables. The RNN-anticipated EHO's accuracy was compared to that of three other popular approaches, including ANN, HHO, CFA, and MOA. Strict statistical criteria and a multi-criteria approach were principally used to assess the predictive power of the developed models. The model is also examined using fresh, independent data that wasn't part of the initial dataset. The hybrid RNNEHO model performed better in predicting the displacement amplitude of footing lying on Geogrid-reinforced beds than the other benchmark models. Last but not least, the sensitivity analysis was used to highlight how input parameters might affect the estimate of displacement amplitude.

Планирование оптимальной загрузки железнодорожного транспорта горнодобывающей компании

The article considers the problem of planning the optimal loading of freight trains on a limited railway network – the network of a mining company. Two variants are illustrated. In the first variant only one type of locomotives operates on the railway network. In the second variant there are different types of locomotives. The types of lo-comotives are determined by their carrying capacity. The algorithm of scheduling multiple locomotives in a network is a combination of solutions for particular scheduling problems for each locomotive subject to the restrictions on their joint movement. Structurally, the set of possible locomotive schedules is a set of system states at discrete points in time. The state at each moment of time describes the location of each locomotive at a particular station and the amount of cargo transported. Thus, two consecutive states unambiguously determine the routes of locomotives. To describe a complete picture of all possible states and the sequence of their transitions from one state to another are represented in the form of a tree. There is proposed an algorithm for decreasing the variants of schedules by comparing the states in the tree nodes at each step and excluding the branches of states that would knowingly lead to a non-optimal schedule. The problem statement including several locomotives of different types, the solution algorithm and its application to a particular case are presented. In the formulation of the task the criterion of optimality for comparing different schedules is the minimum completion time of transporting the necessary volume of cargo. The additional criterion is total operating time of all locomotives, which is used only in case of equality of the main criterion for several schedules.

Early Identification of Unbalanced Freight Traffic Loads Based on Wayside Monitoring and Artificial Intelligence.

The identification of instability problems in freight trains circulation such as unbalanced loads is of particular importance for railways management companies and operators. The early detection of unbalanced loads prevents significant damages that may cause service interruptions or derailments with high financial costs. This study aims to develop a methodology capable of automatically identifying unbalanced vertical loads considering the limits proposed by the reference guidelines. The research relies on a 3D numerical simulation of the train-track dynamic response to the presence of longitudinal and transverse scenarios of unbalanced vertical loads and resorting to a virtual wayside monitoring system. This methodology is based on measured data from accelerometers and strain gauges installed on the rail and involves the following steps: (i) feature extraction, (ii) features normalization based on a latent variable method, (iii) data fusion, and (iv) feature discrimination based on an outlier and a cluster analysis. Regarding feature extraction, the performance of ARX and PCA models is compared. The results prove that the methodology is able to accurately detect and classify longitudinal and transverse unbalanced loads with a reduced number of sensors.

En Kısa Yol Optimizasyonlarında Floyd-Warshall Algoritması: Lojistik Merkezler Örneği

Lojistik merkezler taşımacılık, depolama, elleçleme, dağıtım, gümrükleme, ayrıştırma, ithalat, ihracat ve transit işlemler, sigorta ve bankacılık, altyapı hizmetleri, danışmanlık ve üretim vb. faaliyetlerin birbiriyle uyumlu bir şekilde yürütülmesine ve olası taşıma yöntemlerinin bir arada sunulmasına hizmet eden önemli tesislerdir. Yük talebinin sürekli olması nedeniyle yük taşımacılığının da kesintisiz, en kısa yoldan, yakıt tüketimi ve taşıma süresi açısından da optimal bir şekilde gerçekleştirilmesi gerekmektedir. Bu çalışmada yük trenlerinin lojistik merkezlere en kısa yoldan ulaşması problemi ele alınmıştır. Literatürde lojistik köylerle ilgili yazın taraması yapıldığında; lojistik merkezlerin, lojistik sektörüne yapmış olduğu katkılar incelenmiş, güçlü ve zayıf yönleri ortaya konmaya çalışılmış, etkin ve verimli çalışması hakkında önerilerle ilgili çalışmalar gözlemlenmiştir. Fakat bu çalışmada; konuya mühendislik uygulamaları yaklaşımıyla, ülke genelinde faaliyet gösteren on iki lojistik merkezin yanı sıra yapım ve ihale aşamasında yer alan yedi adet lojistik merkez de çalışma kapsamına dâhil edilerek, lojistik merkezler arasında güzergâh seçimi için en uygun sonuç elde etme amacı güdülmüştür. En kısa yol problemlerinin uygulama alanı genellikle bir şebekede/ağda yer alan noktalar arasında en kısa mesafenin belirlenmesi olup, çalışmada şebekedeki herhangi iki düğüm arasındaki en kısa yolun belirlemesi açısından Floyd-Warshall Algoritması tercih edilmiştir. Bu amaçla ulusal demiryolu ağı için toplam 33 düğümden oluşan bir çizge oluşturulmuş ve en kısa yolun hesaplanması için Floyd-Warshall algoritması Python programlama dilinde kodlanarak çözülmüştür ve toplam on dokuz adet lojistik merkez arasında en kısa yol/yollar tespit edilmiştir.

Possibility to apply unified methodology in vibration analysis for long lasting and impulse sources, in terms of influence on people in buildings

The present work addresses the problem of unified methodology use for vibration analysis caused by various anthropogenic sources. The experimental part of the paper contains analysis and results comparison of the vibration, induced by freight train passages and hammer percussion. Ground vibrations are important for the civil engineering objects condition since the vibration induced by train is transmitted through the ground to the foundation and structure. Ground vibration can also be a source of disturbance for the residents. However, various factors cause vibration that varies in both intensity and frequency measures. The analysis of vibration timelines, running RMS and Fourier spectra are applied. The major part of the dissertation is the analysis of RMS accelerations and velocities in one-third octave frequency bands in 1 to 80 Hz spectrum, and comparison to the background vibration noise, recorded in the same localisation. The different values of time-window observation are applied to analyse the results. The results of long lasting cargo-induced vibrations are less dependent on time-window duration than the results of impulse-induced vibrations. The acceleration and velocity analysis results are compared to the literature data concerning the ground vibration caused by railway transport and mining activity. The paper indicates the possibility to apply unified methodology for vibration analysis caused by both long-lasting sources, as trains and short-lasting ones, as industrial blasts or mine tremors. The results indicate an optimal time window for vibration measurement that would enable to automate vibration monitoring.

Analysis of Train Travel Patterns Case Study of Bogor Double Track Construction - Sukabumi

In this study the aim is to analyze the problem of train travel that occurs with the change from single track to double track as well as changes in the layout of the emplacements, which increase the frequency of passenger and freight train trips. The data used in this study are primary and secondary. Primary data includes existing data on the Bogor-Sukabumi operation pattern obtained by interviewing West Java BTP and KAI employees. Secondary data includes data on train star formation, the type and number of trains, signal service time, and the speed of passenger and freight trains. In the planning of road plots in the Detailed Design of Double Tracks Between Bogor - Cigombong, it is not directly affected by traffic capacity. This is because road plots can be divided into several block plots, which is very different from the single-lane system. To reduce Headway or the same as to increase traffic capacity, simply by adding IB (Intermediate Block) between the distances of AB stations (AB (km) S) in the formula, if 1 (one) IB is installed, then the distance of the road plot is divided by two, if 2 (two) IBs are installed, then the distance of the road plot is divided by three and so on. The analysis study of operational patterns on the Bogor-Sukabumi line shows that with the plan to increase the frequency of trains and the construction of a double track, there will be a decrease in the Headway from 10.38 to 7.1.

Study on the braking distance of composite brake blocks covered with ice for freight trains in winter

In winter, some freight trains with composite brake blocks experience unexpected long braking distances, which seriously jeopardizes running safety. The reasons for the long braking distances are still not completely understood, and therefore it is difficult to suggest preventive measures. Up to now, it has not really been studied how a layer of ice that is often found between the brake block and the wheel influences the braking process. To investigate whether ice influences the braking distance, a numerical model is built. Ice thickness, ambient temperature, initial speed, and axle load/brake pressure are parameters that can be varied in the model. Results are checked against available on-track tests. The simulation results show that ice significantly influences the braking distance. The impact of ice on the braking distance increases when the ambient temperature, initial speed, and brake pressure are low, which is consistent with available field test reports. The results also show that a conditioning brake, a high brake pressure and a small clearance between the wheel and brake block can efficiently reduce the impact of ice on the braking distance of freight trains with composite brake blocks in winter.

Effects of mixed marshalling modes on longitudinal freight train dynamics

Mixed freight trains have more diversified vehicle characteristics and train combination modes than unified freight trains, so it is more difficult for mixed freight trains to predict the accident caused by longitudinal impulse. At present, train dynamics theories and numerical simulation methods have been increasingly used to reduce longitudinal train impulse and decrease freight wagon instability. According to these research experiences, this paper focuses on the marshalling modes of mixed freight trains and their effects on the longitudinal in-rain forces. For this purpose, an advanced simulation model for mixed freight trains was developed and several typical mixed marshalling modes were designed and simulated. The results indicate that, for the mixed train including empty and loaded wagons, empty wagons should be arranged at the tail of the train and should avoid being marshalled together. For the mixed train including marshalled wagons with various actual live loads or nominal axle loads, heavier wagons should be centrally arranged in the front part of the train, and meanwhile marshalled wagons should avoid being sorted by weight in the concave and ascending distribution mode. For the mixed train including marshalled wagons with various body types, container flat wagons and oil tank wagons should be arranged as much as possible in the front of the other wagons.

Machine learning-assisted macro simulation for yard arrival prediction

Increasing the modal share of the single wagonload transport in Europe requires improving the reliability and predictability of freight trains running between the yards. In this paper, we propose a novel machine learning-assisted macro simulation framework to increase the predictability of yard departures and arrivals. Machine learning is applied through a random forest algorithm to implement a yard departure prediction model. Our yard departure prediction approach is less complex compared to previous yard simulation approaches, and provides an accuracy level of 92% in predictions. Then, departure predictions assist a macro simulation network model (PROTON) to predict arrivals to the succeeding yards. We tested this framework using data from a stretch between two main yards in Sweden; our experiments show that the current framework performs better than the timetable and a basic machine learning arrival prediction model by R2 of 0.48 and a mean absolute error of 35 minutes. Our current results indicate that combination of approaches, including yard and network interactions, can yield competitive results for complex yard arrival time prediction tasks which can assist yard operators and infrastructure managers in yard re-planning processes and yard-network coordination respectively.