Edge Of Rail Research Articles

Predicting the wear on the non-working side of the rail profile registration method and its validation

Abstract Rail cross-section profile detection can assess the wear and tear of measured rails, providing crucial references for railway maintenance and upkeep. It is challenging to use the conventional method to register only the profile of rail head detection accurately. After the rail edge adjustment in some conventional railways, it becomes difficult to determine the base point of rail profile registration. Due to the wear of non-working edge of rail, a rail profile registration method is proposed. Firstly, a wear prediction model based on the generalized regression neural network is constructed by optimizing smoothing parameters through ten-fold cross-validation to achieve the optimal values. This model predicts the wear values on the non-working rail edge, providing reliable coordinates for two wear points as alignment reference points. Secondly, an initial alignment between the measured profile and the target profile is achieved using the nearest point iterative algorithm, which ensures that both profiles are in the same region and oriented similarly. Thirdly, the weight is assigned to the wear measurement points based on their respective wear values. The predicted positions of wear points are applied for calculating the translation and rotation parameters. These parameters could align the measured profile and facilitate the final profile alignment. Lastly, the experimental profiles under rail adjustment conditions were registered, verifying the accuracy of the proposed method. The research results indicate that under rail adjustment conditions, the mean squared error (MSE) between the calculated and actual values of lateral wear is 0.094 mm2, which is lower than the MSE from manual measurements. The calculated lateral wear value for experimental profiles achieved high alignment and calculation accuracy. This method can be applied in practical projects, providing an effective solution for rail head profile alignment and serving as a reference for profile alignment on the non-working rail edge with incomplete measurement data.

Self-adaptive rail edge detection for trams based on mathematical morphology.

With the growing number of tram operation lines, tram-related traffic incidents, particularly train collisions, have become a major issue. Therefore, the ability to identify foreign objects on a track is critical to tram operational safety. Accurately identifying the rail edge is a critical technology for recognizing the track area and providing early warnings of potential threats. Therefore, this study proposes a self-adaptive rail-edge detection algorithm that uses mathematical morphology and computer vision technology to accurately extract rail edges. The performance of the proposed algorithm was compared to that of existing algorithms, including the Canny algorithm and two other methods described in publication. Three scenes in the level crossing area of trams were considered as the research objects, and the effects of two types of noise in the image were explored in terms of the investigated using mean square error (MSE), peak signal-to-noise ratio (PSNR), and computational time. The results showed that the proposed model exhibited strong robustness for different scenes, particularly in the presence of noise. This suggests that the proposed algorithm could be used in early warning systems of trams to identify rail edges.

Hybrid deep learning architecture for rail surface segmentation and surface defect detection

AbstractRail surface defects (RSDs) are a major problem that reduces operation safety. Unfortunately, the existing RSD detection systems have very limited accuracy. Current image processing methods are not tailored for the railway track and many fully convolutional networks (FCN)‐based methods suffer from the blurry rail edges (RE). This paper proposes a new rail boundary guidance network (RBGNet) for salient RS detection. First, a novel architecture is proposed to fully utilize the complementarity between the RS and the RE to accurately identify the RS with well‐defined boundaries. The newly developed RBGNet injects high‐level RS object information into shallow RS edge features by a progressive fused way for obtaining fine edge features. Then, the system integrates the refined edge features with RS features at different high‐level layers to predict the RS precisely. Second, an innovative hybrid loss consisting of binary cross entropy (BCE), structural similarity index measure (SSIM), and intersection‐over‐union (IoU) is proposed and equipped into the RBGNet to supervise the network and learn the transformation between the input and ground truth. The input and ground truth then further refine the RS location and edges. Conveniently, an image‐based model for RSD detection and quantification is also developed and integrated for an automatic inspection purpose. Finally, experiments conducted on the complex unmanned aerial vehicle (UAV) rail dataset indicate the system can achieve a high detection rate with good adaptation capability in complicated environments.

A Machine Vision System Based on Driving Recorder for Automatic Inspection of Rail Curvature

Because of long distance of railway lines, it is difficult to find an appropriate method to inspect the rail track condition efficiently and accurately. In this article, a machine vision system based on driving recorder and image signal processing is proposed to evaluate the rail curvature automatically. The proposed machine vision system consists of four modules including the video acquisition module, the image extraction module, the image processing module, and the track condition assessment module. Three classic edge detection methods are adopted and compared for rail edge detection. In line with the videos of driving recorder, coordinate systems for train and rail are defined in the Lagrangian space, and the track curvature is estimated using the proposed chord offset method and double measurement method. For evaluating the track condition, an index describing the concordance between the train and track is defined. In the case study, a set of videos from the driving recorders of trains during their in-service operations are analyzed by the proposed technique, and the obtained results are verified by comparison with those obtained by a track geometry inspection vehicle. It is shown that the proposed technique can evaluate the track curvature accurately. Moreover, the influence of the position of deployed driving recorder, the focal length and anti-shake of camera on the accuracy of evaluation results is discussed. It is testified that the proposed technique provides a simple and reliable way to inspect the track curvature.

A preliminary study on enhancing safety of contact features in the terrain park

ObjectivesTerrain park riders use contact features such as fun boxes and rails. Typical fun box and rail features have a design characteristic that can be changed to improve safety. Fun box edge coping and edges of rails are typically constructed of soft steel. Ski/snowboard edges (HRC50) can easily become engaged in the softer metal, causing a chip to develop, suddenly stopping the rider, probably causing a fall and possible injury. The aim of the study is to examine the effect of terrain park running surface hardness on chip development. DesignTesting on steel specimens was performed to research chip development generated by a ski/snowboard edge on steel used in the construction of contact features and on steel that is proposed for such use. An apparatus was constructed to simulate a ski/snowboard edge moving perpendicular to the long axis of coping or rail edge. MethodsThe author performed observation, photographic documentation, metallurgical testing and environmental testing of various contact features at different ski area terrain parks. Several steel specimens of varying hardness were tested at various load levels to study the propensity of chip development by ski/snowboard edges. ResultsTesting of steel samples showed that increasing the hardness of the rail steel or coping steel reduced the propensity for a ski/snowboard edge to engage in the coping or rail. ConclusionsIncreasing steel coping and rail contact surface hardness to HRC 50 and above will likely reduce engagement by steel snowboard/ski edges, which in turn is expected to reduce the chance of a fall and injury.

Dosimetric Evaluation of the QFix kVueTM Calypso Couch Top.

Purpose:To evaluate the dosimetric accuracy of the default couch model of the QFix kVueTM Calypso couch top in the treatment planning system.Methods:With the gantry 180°, field size 20 × 20 cm, 6 MV, we measured the depth dose, off-axis dose, and dose plane of different depths in the phantom with the couch rails in and out, respectively. Isocenter doses at different angles were also obtained. The results were compared to the doses calculated using the default couch top model and the real scanned couch top model. Then we revised the default model according to the measured results.Results:With “Rails In,” the depth dose, off-axis dose, and dose plane of the default couch top model had a big difference with the dose of the real scanned couch top model and the measured result. The dose of the real scanned couch top model was much closer to the measured result, but in the region of the rail edge, the difference was still significant. With “Rails Out,” there was a minor difference between the measured result, the dose of the default couch top model and the real scanned couch top model. The difference between the measurement and the default couch top model became very small after being revised.Conclusions:It is better to avoid the beam angle passing through the couch rails in treatment plans, or you should revise the parameter of the QFix kVueTM Calypso couch top model based on the measured results, and verify the treatment plan before clinical practice.

A multi-field coupling model for the magnetic-thermal-structural analysis in the electromagnetic rail launch

The magnetic-thermal-structural performances (MTSP) in an electromagnetic rail launcher have a significant influence on the successful launch capability. However, it is difficult to explore the MTSP directly through the experimental measurement due to the approximately adiabatic processes in the in-bore environment of the launcher, which further limits us to understand the multi-field properties in the electromagnetic launch process. Considering the interaction between the magnetic field and the thermal field, a transient multi-field coupling model is proposed to investigate the MTSP for the electromagnetic launch based on the finite element method in this paper. The model validation is presented through a comparison of the model prediction with the experimental data of the magnetic flux density and the temperature. The MTSP for an electromagnetic railgun are then analyzed in detail with the effect of the pulse power supply parameter and rail sizes. The results show the pulse power supply parameter has a significant effect on the MTSP near the electromagnetic railgun breech and the rail damage can be decreased with a larger rail size. Moreover, we found the rail was most easily to damage at the rail edge position of the inner sidewall, which is consistent with the groove-shaped damage position in the rail after an experimental test. The results of these investigations will help improve the design of an electromagnetic launcher.

Detectability of Rail Defects by Magnetic Flux Leakage Method

The ability of the Magnetic Flux Leakage (MFL) method to detect flaws in railway rails in two different ways has been studied. First, a three-dimensional computer simulation of the leakage of magnetic flux around a transverse crack in the rail head was carried out to determine the relationship between the main characteristics (size and depth) of the defect and the magnetic sensor signal. Second, signals were analyzed from more than 600 actually confirmed defects of the rail track, enabling statistically determined conclusions on the detectability of various types of flaws by magnetic and ultrasonic methods. It has been established that the MFL method detects rail head defects with the critical size at a depth of up to 20 mm under the upper rail edge. In general, the revealed defects constitute more than 90% of hazardous damage to rail head; this confirms the high efficiency of the MFL method in comparison with acoustic methods, which are also traditionally used in rail non-destructive testing.

Station avenue: high-speed rail’s missing link. Assessing pedestrian city-station routes for edge stations in Spanish small cities

High-speed rail edge stations, which are located within the urban fabric limits of a city, have generally a good access through motorised transportation modes while the pedestrian/bicycle access becomes, in many cases, very difficult. This paper assesses the quality of pedestrian routes linking high-speed rail edge stations to the city centre, considering physical aspects such as footpaths width, characteristics of the built environment or detours at street crossings. The assessment demonstrates that a pedestrian route could be redesigned to minimise discontinuities and to improve walkability, extending the walkable distance threshold through an adequate design. The proposed methods could provide a useful tool for cities to identify the most appropriate footpath to create convenient and legible pedestrian routes with walkable promenades for edge stations, because, in general, there are no specific strategies or policies to favour these walkable connections. In many cases, these edge stations are hidden city gates and the station-city pedestrian connection is the missing link in this intermodal transport chain.

Research on Quick Superplastic Forming Technology of Industrial Aluminum Alloys for Rail Traffic

Quick superplastic forming is a new technology, which combines hot drawing preforming and superplastic forming. It makes full use of the high speed of hot drawing and good formability of superplasticity. For aluminum alloy complex components, the difficulties of stamping and low speed of superplasticity be perfect solved. In this work, the best forming process of side wall outer panel of metro vehicle was determined by forming experiment using quick superplastic forming technology. The high-speed rail edge skin with a very small fillet shape (R≤4 mm) and the large-size subway door frame part (h≈80 mm) formed by straight wall deep drawing were manufactured, using industrial aluminum alloy sheet with thickness of 4 mm. Meanwhile, the formed parts show the advantages of high dimensional accuracy and uniform wall thickness distribution, and the mechanical properties of formed parts can completely meet the requirements as well, which demonstrates the desirable efficiency, low cost and feasibility of this new technology.

A railway increases the abundance and accelerates the phenology of bear‐attracting plants in a forested, mountain park

AbstractVegetation enhancement along railways has not been well studied, despite high rates of mortality from train strikes across numerous species, including sensitive populations in protected areas. This situation describes grizzly bears (Ursus arctos) in the mountain parks of Canada, where train strikes have become the leading source of known mortality. We hypothesized that attraction by bears to railways occurs partly because of increases in the richness, diversity, cover, and maturation rate of plants consumed by bears relative to adjacent forest and that this effect may increase with elevation. We quantified and compared responses in plants used by bears to the railway (ballast), forest edge, and within adjacent forest for two growing seasons (May–October) at 19 locations spanning an elevational gradient in Banff and Yoho National Parks in the Canadian Rocky Mountains. Overall, richness, diversity, and total cover of plants consumed by bears were greatest at the forest edge. On the forest edge or ballast, flowering rates of some species were over three times higher and fruit occurrence was up to five times higher than 50 m into the adjacent forest. Enhancement of berry productivity along rail edges increased with elevation. Buffaloberry (Shepherdia canadensis), an important regional pre‐hibernation resource, had more fruit, faster ripening, and higher sugar content for shrubs located within 15 m of the rail than within surrounding interior forest. Our results demonstrate that railway edges can increase the quantity and quality of palatable vegetation resources of both native and introduced species, potentially increasing strike risk for bears and other wildlife. Potential mitigation of this risk could include removal of attractants along the rail, particularly at locations where other factors increase the risk of collisions, and creation of forest openings, either through natural processes or through forest modification that would provide forage in less risky habitats.

Sleeper embedded insulated rail joints for minimising the number of modes of failure

Insulated rail joints (IRJs) identify broken rails and train locations in railway signalling circuitry, which are critical to the rail safety operation. Unfortunately, IRJs exhibit several failure modes due to complex interaction between their components, the load spectra and the support conditions. A novel idea of simplifying the design of the IRJs consisting of only two pieces of insulated rails embedded into a concrete sleeper in such a way that the free ends of the rails at the gap attain stiffness commensurate to that of the current designs where the gapped rails are connected with two joint bars (also known as fishplates) one on each side of the rail web with the assembly resting on top of sleepers. The advantages of the new design are that it exhibits stability levels comparable to the current designs with fewer components and hence fewer failure modes. A multi-objective optimisation framework was used for the development of the new design that enables safe passage of train wheels across the gap between the rails embedded in concrete sleepers. Feasibility of the sleeper embedded gapped insulated rails under traffic loading is demonstrated through a dynamic analysis of a rail wheel rolling on top of a selected optimal design from the Pareto front. The deformation components of the rail edge at the gap of the new design are shown to be lower than that of the classical insulated rail joints.

PRT simulation research

The paper presents analyses results of PRT vehicle driveability in a ¼ scale conducted with the application of a simulation model for a straight line driving conditions and when driving on a curve. The results of the present work will be used in the analysis of a physical motion model in a laboratory stand reflecting a railway system of the stand. The paper discusses the first stage of research in the process of virtual pre-prototyping which is to be finalized with the construction of a non-commercial vehicle prototype. In the construction of the simulation model, particular attention has been paid to three issues. First of all, a correct description of design features connected with the lack of so called centring mechanism – and not profiled tyred wheels independently embedded in the axes of the set. Secondly, a proper description of a turning mechanism with the use of a leading rollers system alongside the rail edge. Thirdly, the use of linear motor for the vehicle drive. The simulation model has been developed within MBS environment. For the description of tyred wheels, the library of TNO Delft Tyre has been used. Vehicle motion stability has been tested on the straight and curved track sections. The research has been financed within the framework of ECO mobility project.

Application of Wavelet Transform into Precise Localization of Railway Rail Edges in Visual Diagnostic of Track

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Thermal Computation in Railgun by Hybrid Time Domain Technique 3-D-FEM-IEM

Thermal energy in railgun is unwanted and generated by ohmic losses that are dependent to the current implied, rail dimensions, electrical conductivity (σ), and specific heat (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> )-σ and C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> are functions of temperature. Using achievement formula by intelligent estimation method, the current density and ohmic losses on the cross section of the rail are computed. Ohmic losses are the source heat and utilized heat equation that are used to compute thermal distribution and temperature that are compared with other results in some papers. This paper chose , h = 30 mm , w = 10 mm, and copper for the rail material and a method to compute the thermal distribution on the surface of the rail and side rail edges. Effects of rail dimensions on the temperature in time domain are calculated and shown in the figures. Rail materials are investigated with copper and aluminum in which the average temperature of both materials on the rail surface is calculated and compared.

Numerical study of the mechanical deterioration of insulated rail joints

Numerical simulations are performed to study plastic deformation and fatigue impact of an insulated joint. The simulations feature a sophisticated constitutive model capable of capturing ratcheting under multi-axial loading conditions. Calculation results are presented in the form of effective strain magnitudes, plastic zone sizes, and multi-axial low cycle fatigue parameters. The simulation results indicate that the main damage mechanism at insulated joints is ratcheting and not low cycle fatigue. A parametric study quantifies effects of increased vertical and longitudinal load magnitudes, as well as the effect of an increased insulating gap. In particular, longitudinal loading is indicated as being severely deteriorating for the rail in the vicinity of the joint. Finally, the effect of rail edge bevelling is assessed and found to be small for the case studied.

Analysis of Railgun Barrel Material

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The effect of the number of shots on multiple-launch railgun barrel material performance under significantly high current conditions was studied. Material analysis was conducted on rail samples from four sets of experiments involving increasing number of shots. Cross sections of samples from two locations in the copper rail were examined using a variety of metallographic techniques. During each shot a thin film of molten aluminum from the armature deposited on the rail surface. The deposit became thicker and multilayered with increasing number of shots and was thicker in the bottom half of the vertically oriented rails than in the top half. Preferential removal of material occurred along both rail edges, which resulted in the formation of grooves over the length of the rails. Grooves were deeper near the top edge of the rails compared to the bottom edge. A proposed mechanism for grooving is dissolution of the rail material into molten aluminum flowing toward the rail interior due to aerodynamic drag and over the rail edge due to surface tension effects, assisted by extremely high rail edge temperatures. Asymmetry in the armature–rail gap due to magnetic interactions with the support structure may be the cause of asymmetry in deposit thickness and groove depth. </para>

Wear, plastic deformation and friction of two rail steels—a full-scale test and a laboratory study

Form change due to wear and plastic deformation on a rail can reduce the service life of a track. The purpose of this investigation was to study the development of these damage mechanisms on new and 3-year-old rails in a commuter track over a period of 2 years. The experimental results from the form measurements show that there was a significant change in rail profile due to wear as well as to plastic deformation. Plastic deformation and wear was a continuing process even for rail that had been in service for 5 years. The plastic deformation mechanism was plastic ratchetting. Compared with the UIC 900A grade rail, the form change was less for the UIC 1100 grade rail. However, the contact situation in terms of sliding velocity and contact pressure had more influence on form change than the change of material. The results from 3D surface measurement showed that there were different wear mechanisms involved at different parts of the rail. Mild wear dominated at the rail head, but at the rail edge severe wear clearly influenced the amount of wear. The severe wear showed traces of seizure. Material tests were performed on two different testing machines: a two-roller and a pin-on-disk machine. On the basis of results from the material testing, a simple wear map was constructed. In the wear map, the wear coefficient is presented as a function of sliding velocity and contact pressure. The results from laboratory tests showed that wear coefficient depended strongly on sliding velocity. The increase in the wear coefficient when increasing sliding velocity was due to a change of wear mechanism from mild wear to severe wear.

ON THE LATERAL STRENGTH OF THE RAILWAY TRACK (Part 2)

In the previous paper (Part 1) the author determined the condition for rapidly developing course deflection. It was the condition for the first cross-tie to slip and the study was made from the tendency of lateral pressure to be highly concentrated near the acting point. In the present paper the condition under which the following cross-ties start slipping is determined.The relation of the moduls of foundation against rail torsion to wheel load is discussed.When the lateral wheel pressure increases over the limit value, the weeel creeps up towards the outer edge of rail and finally is derailed. So the strength of the track which can bear the limit lateral pressure is considered satisfactory.