Journal articles on the topic 'Rail'
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1
Sasaki, Toshihiko, Osama Yaguchi, and Yuichi Kobayashi. "A Study on Area Detector Type Diffraction Stress Measurement and its Application to Shelling Problem in Railway Tracks." Materials Science Forum 638-642 (January 2010): 2458–63. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2458.
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In order to study on the effects of grinding of rail head on rolling contact fatigue of rails, residual stress measurements were conducted for rails processed under different grinding conditions. In this study, residual stresses in rails used for a service line were measured with the method of X-ray stress measurement. The triaxial stress analysis was conducted using a new method for an area detector type X-ray stress analysis proposed by the authors. Four grinding conditions were used to rail specimens. The distributions of residual stresses in the surface layer of the rail head were obtained. It was found that the tensile residual stresses were generated at the field-side of the ground rai1, and that the triaxial stress state was formed in the surface of the rail head widely.
2
Mazilu, Traian, and Mihai Cornel Leu. "On the Modelling of Rail Joint." Materials Science Forum 957 (June 2019): 33–42. http://dx.doi.org/10.4028/www.scientific.net/msf.957.33.
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Jointed track is still used to build the secondary lines where the maximum speed does not exceed 100-120 km/h. Jointed track construction is based by the fact that the rails are joined end-to-end via the rail joints in order to assure the continuity of the rolling surface of the rails. The rails are jointed using two metal joint bars (fishplates) bolted to the ends of adjoining rails. The rail joints are featured with small gaps to allow the thermic expansion of the rails when the environmental temperature is higher than that during the fitting. In this paper, an analytical model for the rail joint considering the influence of the joint gap is presented and analysed. The model consists of three Euler-Bernoulli beams, two for the rail ends of the rail joint and the third beam for the two joint bars, connected to the rail ends by a Winkler layer. The concept of weakness of the rail joint (rail joint deflection/continuous rail deflection) is introduced and used to analyse the static behaviour of three types of rail joints used at CFR (Romanian Railways). The influence of the joint bars length and bending stiffness, and the influence of the joint gap length upon the rail joint weakness is pointed out.
3
Dumitriu, Mădălina. "Numerical Analysis of the Vertical Bogie Accelerations at Failure of the Damper in the Primary Suspension of the Railway Vehicle." Materials Science Forum 957 (June 2019): 43–52. http://dx.doi.org/10.4028/www.scientific.net/msf.957.43.
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Jointed track is still used to build the secondary lines where the maximum speed does not exceed 100-120 km/h. Jointed track construction is based by the fact that the rails are joined end-to-end via the rail joints in order to assure the continuity of the rolling surface of the rails. The rails are jointed using two metal joint bars (fishplates) bolted to the ends of adjoining rails. The rail joints are featured with small gaps to allow the thermic expansion of the rails when the environmental temperature is higher than that during the fitting. In this paper, an analytical model for the rail joint considering the influence of the joint gap is presented and analysed. The model consists of three Euler-Bernoulli beams, two for the rail ends of the rail joint and the third beam for the two joint bars, connected to the rail ends by a Winkler layer. The concept of weakness of the rail joint (rail joint deflection/continuous rail deflection) is introduced and used to analyse the static behaviour of three types of rail joints used at CFR (Romanian Railways). The influence of the joint bars length and bending stiffness, and the influence of the joint gap length upon the rail joint weakness is pointed out.
4
Obara, T., N. Kumagai, and T. Takiguchi. "Development of Hybrid Rail Brake." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 209, no. 2 (July 1995): 61–65. http://dx.doi.org/10.1243/pime_proc_1995_209_257_02.
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In Japan three types of rail brake were tested in the field. They were the eddy current rail brake, the electromagnetic rail brake, and the hybrid rail brake. The eddy current type, which does not come into contact with rails, needs high current and greatly increases the temperature in rails. The electromagnetic type which attracts rails and achieves braking by frictional force cannot generate a stable braking force. Therefore the authors developed a hybrid rail brake, which has advantages over the other two types. This type does not need as much current, and keeps rail temperature low.
5
Kumar, S., and S. P. Singh. "Rail Head Geometry, Rail Rolling and Wheel-Rail Contact Tilting Analysis for Heavy Axle Loads." Journal of Engineering for Industry 111, no. 4 (November 1, 1989): 375–81. http://dx.doi.org/10.1115/1.3188775.
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This paper presents analytical considerations which are important to design a rail head for reducing rail damage due to heavy axle loads. There are two important parameters of design of rail crown: (1) the wheel tread rail crown contact stress and (2) the contact tilt angle called the β angle. Contact should not be allowed to move out of the rail crown. Analysis of lateral oscillations of new and worn wheel sets shows that they do not impose an engineering constraint on the choice of rail crown radius. Rail rolling on curves due to lateral creepage forces is however of great importance in rail loading and stresses. The point of contact location is significantly affected by such roll. For the two commonly used rails, 132 RE and 136 RE, this roll results in the contact moving to the part of the rail head with radius of 1 1/4 in. Such movement of the contact also develops rapidly when hollowed worn wheels roll on flattened worn rails. It is pointed out that this condition results in forces higher than the wheel load and stresses more than twice the value developed when the contact is within the rail crown and that this is most likely responsible for many of the rail failure problems including cracking, shelling, and fractures. A design analysis of rail crown including Hertzian contact and rail twist considerations shows that none of the three current rails analyzed satisfy the criteria developed for good rail head design. A suitable ellipitical crown should prove better. Finally a systems approach to rail wheel interaction with a number of design recommendations is given.
6
Wei, Kai, Rui Ying Chen, and Yu De Xu. "Rail Profile Wear on Curve and its Effect on Wheel-Rail Contact Geometry." Advanced Materials Research 779-780 (September 2013): 655–59. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.655.
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The paper has carried out continued tests on a curve of a heavy haul railway in China for its rail profiles. Based on the data, the paper has counted the development of the rail profile wear, and then analyses the influence of wheel-rail contact geometry on the rail profile wear. The results show that the wear of high rails develops around the rail corners, while the one of low rails around the rail top. The development of the rail wear speeds up after the transport mass passes 210MGT. The wheel-rail contact geometry deteriorates when the transport mass grows up to 60MGT and lower than 210MGT.
7
Takahashi, Shunichi, Toshihiko Sasaki, Yukio Sato, Kengo Iwafuchi, Hiroshi Suzuki, Yukio Morii, Yasuto Kondo, Ryoichi Monzen, and Yukio Hirose. "Application of Neutron Diffraction Technique to Industrial Materials." Materials Science Forum 571-572 (March 2008): 57–62. http://dx.doi.org/10.4028/www.scientific.net/msf.571-572.57.
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As an important industrial problem, the rolling contact fatigue damage is accumulated in rails during the repeated passage of trains over the rails, and rail failures may occur from the cracks grown in the rails. In order to prevent such rail failures, the estimation of the behavior of internal rail cracks is required based on the exact engineering analysis model as well as conducting rail test to search rail defects. The purposes of this paper are to apply the neutron stress measurement to rails, and to obtain residual stress state in the rails for the above purpose. The rail samples used were those that have been used in service line in Japan for about six years (222 million gross tons). The neutron measurement was conducted using the Residual Stress Analyzer (RESA) of the Japan Atomic Energy Agency (JAEA). The present measurement of stresses in rails by the neutron diffraction method was the first attempt in Japan.
8
Choi, Jung-Youl, Sang-Won Yun, Jee-Seung Chung, and Sun-Hee Kim. "Comparative Study of Wheel–Rail Contact Impact Force for Jointed Rail and Continuous Welded Rail on Light-Rail Transit." Applied Sciences 10, no. 7 (March 27, 2020): 2299. http://dx.doi.org/10.3390/app10072299.
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In this study, the measured track impact factor induced by the wheel–rail contact impact force of each test section (two continuous welded rails on slab tracks and rail joint on a ballasted track) was compared with the design track impact factor under service conditions of a curved light-rail transit system. The measured track impact factor (TIF) was estimated from the measured dynamic wheel load and vertical rail displacement at each test section. In the case of the rail joint section, the rail joint was found to directly affect the track impact factor. Moreover, the dynamic wheel load fluctuation and vertical rail displacement were found to be significantly greater than those of the continuous welded rails (CWRs) on slab tracks. In addition, vertical rail displacements were measured by field measurement and finite element analysis (FEA) was conducted to simulate dynamic wheel load on the jointed rail. Using the field measurements, the rate of dynamic wheel load fluctuation and the TIF were calculated for the CWR and rail joint sections. Subsequently, the calculated TIF values were analytically validated through a comparison with the measured vertical rail displacement, the results of FEA, and the designed TIF for rail joints and CWRs. Finally, the TIF measured by field measurement was compared with the result predicted by FEA. The difference between the results of field measurements and FEA for vertical rail displacement was within approximately 4%.
9
Ma, Xiaochuan, Ping Wang, Jingmang Xu, and Rong Chen. "Effect of the vertical relative motion of stock/switch rails on wheel–rail contact mechanics in switch panel of railway turnout." Advances in Mechanical Engineering 10, no. 7 (July 2018): 168781401879065. http://dx.doi.org/10.1177/1687814018790659.
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In order to enable the vehicle to change among the tracks, the stock and switch rails are separated and provided with different rail resilience levels on the baseplate in the railway turnout switch panel. Therefore, there will be vertical relative motion between stock/switch rails under wheel loads, and the relative motion will change the combined profile of stock/switch rails and consequently affect the wheel–rail contact mechanics. A method is developed in this article to investigate the effect of the relative motion of stock/switch rails on the wheel–rail contact mechanics along the railway turnout switch panel. First, the possible rigid wheel–rail contact points, called primary and secondary stock/switch rail contact points, are calculated based on the trace line method; second, the actual contact points are determined by the presented equations; finally, the distribution of wheel–rail contact forces on the stock/switch rails is obtained based on the continuity of interface displacements and forces. A numerical example is presented in order to investigate the effect of the relative motion of stock/switch rails on the wheel–rail contact points, stresses, and forces, and the results are presented and discussed.
10
Chen, Zhi Wei, Linan Li, Shi Gang Sun, and Jun Long Zhou. "Wheel-Rail Multi-Point Contact Method for Railway Turnouts." Applied Mechanics and Materials 97-98 (September 2011): 378–81. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.378.
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A calculation method of wheel-rail multi-point contact based on the elastic contact model is introduced. Moreover, the simulation calculation of vehicles passing through branch lines of No.18 turnouts is carried out. The result showed that the acute change of wheel-rail normal force caused by the transfers of wheel-rail contact point between two rails can be avoid by wheel-rail multi-point contact method, and the transfers of wheel-rail normal force between two rails is smoother. The validity of wheel-rail multi-point contact method is verified.
11
Kodokostas, Dimitrios, and Sofia Lambropoulou. "Rail knotoids." Journal of Knot Theory and Its Ramifications 28, no. 13 (November 2019): 1940019. http://dx.doi.org/10.1142/s0218216519400194.
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We work on the notions of rail arcs and rail isotopy in [Formula: see text], and we introduce the notions of rail knotoid diagrams and their equivalence. Our main result is that two rail arcs in [Formula: see text] are rail isotopic if and only if their knotoid diagram projections to the plane of two lines which we call rails, are equivalent. We also make a connection between the rail isotopy in [Formula: see text] and the knot theory of the handlebody of genus [Formula: see text].
12
Li, Yang, JinJie Chen, JianXi Wang, Hu Zhao, and Long Chen. "Study on the residual stress distribution of railway rails." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 23 (May 28, 2020): 4682–94. http://dx.doi.org/10.1177/0954406220927069.
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Rolling contact fatigue damage of rails is significantly influenced by residual stresses. A three-dimensional elastic-plastic finite element model of wheel–rail contact was established in the present study, and the influence of initial stresses resulting from rail manufacturing process on the residual stress distribution of rails was analyzed. The repeated rolling passes were simulated and the stable residual stress distribution of rails was obtained. The influence of factors, such as wheel load, friction coefficient, and longitudinal creep rate, on the residual stress distribution of rails was investigated. It is found that within the limited special scale affected by the wheel–rail contact, the difference between the longitudinal residual stress with initial stresses applied and that without initial stresses applied becomes quite small once enough rolling passes have occurred (i.e., 10 rolling passes). When the initial stresses are applied, the longitudinal residual compressive stress on wheel–rail contact center of the rail is approximately 500 MPa. The residual compressive stress decreases with the increasing depth and changes from compression to tension at the depth of 6 mm beneath wheel–rail contact center of the rail. The wheel load mainly affects the residual stress distribution along the depth direction beneath rail surface. The friction coefficient mainly affects the residual stress distribution on the rail surface. The longitudinal creep rate has a great influence on the longitudinal residual stresses at the surface and along the depth of the rail.
13
Sun, Shuaishuai, Jian Yang, Tanju Yildirim, Donghong Ning, Xiaojing Zhu, Haiping Du, Shiwu Zhang, Masami Nakano, and Weihua Li. "A magnetorheological elastomer rail damper for wideband attenuation of rail noise and vibration." Journal of Intelligent Material Systems and Structures 31, no. 2 (August 30, 2019): 220–28. http://dx.doi.org/10.1177/1045389x19873406.
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The noise and vibration effects of rails can have a significant impact on the environment surrounding the railways. Rail dampers are elements that are attached to the sides of the rail and can improve the track decay rate of rail and then enhance the rails’ ability to attenuate noises and vibrations. However, in practical applications, the most efficient rail damper design still cannot adjust its own parameters to adapt to different requirements because their stiffness and damping are fixed after designed. In this work, a tunable magnetorheological elastomer rail damper that works on the principle of a dynamic vibration absorber has been designed, analysed, characterised, and experimentally tested for the suppression of railway noise and vibration. The new rail damper incorporates variable stiffness magnetorheological elastomer layers, whose stiffness can be controlled by an externally applied magnetic field, to realise adaptive characteristics. Experimental characterisations of the magnetorheological elastomer rail damper were performed with an electromagnetic shaker. Subsequently, theoretical predictions of the track decay rate of a UIC-60 rail with different rail dampers and without rail damper were conducted; simulation results verified that magnetorheological elastomer rail dampers can improve the track decay rate of rail over a wider frequency range compared to conventional rail dampers and thus the performance of the magnetorheological elastomer rail damper outperforms other conventional rail dampers on rail noise reduction.
14
Bui, Thuy-Vy D., John Y. Takekawa, Cory T. Overton, Emily R. Schultz, Joshua M. Hull, and Michael L. Casazza. "Movements of Radio-Marked California Ridgway's Rails During Monitoring Surveys: Implications for Population Monitoring." Journal of Fish and Wildlife Management 6, no. 1 (February 1, 2015): 227–37. http://dx.doi.org/10.3996/092014-jfwm-069.
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Abstract The California Ridgway's rail Rallus obsoletus obsoletus (hereafter California rail) is a secretive marsh bird endemic to tidal marshes in the San Francisco Bay (hereafter bay) of California. The California rail has undergone significant range contraction and population declines due to a variety of factors, including predation and the degradation and loss of habitat. Call-count surveys, which include call playbacks, based on the standardized North American marsh bird monitoring protocol have been conducted throughout the bay since 2005 to monitor population size and distribution of the California rail. However, call-count surveys are difficult to evaluate for efficacy or accuracy. To measure the accuracy of call-count surveys and investigate whether radio-marked California rails moved in response to call-count surveys, we compared locations of radio-marked California rails collected at frequent intervals (15 min) to California rail detections recorded during call-count surveys conducted over the same time periods. Overall, 60% of radio-marked California rails within 200 m of observers were not detected during call-count surveys. Movements of radio-marked California rails showed no directional bias (P = 0.92) irrespective of whether or not playbacks of five marsh bird species (including the California rail) were broadcast from listening stations. Our findings suggest that playbacks of rail vocalizations do not consistently influence California rail movements during surveys. However, call-count surveys may underestimate California rail presence; therefore, caution should be used when relating raw numbers of call-count detections to population abundance.
15
Mei, G. M., G. X. Chen, S. Yan, and R. X. Chen. "Study on a Heuristic Wheelset Structure without Rail Corrugation on Sharply Curved Tracks." Shock and Vibration 2021 (August 12, 2021): 1–14. http://dx.doi.org/10.1155/2021/3874005.
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Rail corrugation on low rails of sharp railway curves is still a difficult problem to solve worldwide. Nearly all low rails of the sharp railway curves incur rail corrugation. In the present study, an active method to remedy rail corrugation was studied. From the viewpoint of the frictional self-excited oscillation of a wheelset-track system causing rail corrugation, the effect of wheelset structures on rail corrugation was studied. Three frictional self-excited oscillation models of wheelset-track systems with different wheelset structures were established, which include a heuristic wheelset structure and two being used in the railway industry. The incidence trends of the self-excited oscillations of these three wheelset-track systems were studied. It was found that the wheelset structure has an important effect on rail corrugation, and that the heuristic wheelset structure can restrain or get rid of rail corrugation. With the parameter sensitivity analysis, it was found that when the friction coefficient between the wheel and rail, rail gauge, rail cant, and sleeper span changes to some extent, the heuristic wheelset structure is robust enough to prevent rail corrugation. The proposed heuristic wheelset structure can be used as a potential solution to rail corrugation on sharply curved tracks.
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Zhou, Jian Hua, Yu Ji, An Chao Ren, and You Deng Zhang. "Analysis of the Generation Cause of Scale Shelling Defects on Running Surface of 60kg/m U71Mn Rail." Advanced Materials Research 291-294 (July 2011): 1062–68. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1062.
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There were different degree scale shelling defects on running surface of 60kg/m U71Mn rail after used on the curve for a period of time, the characteristics and the generating reasons of the defects were analyzed, and the improvement measures were presented. There test results indicated that the scale shelling defects found on rail running surface were a sort of typical rolling contact fatigue damage, which caused mainly by the excessive contact stress, as a result of the wheel long-term contact with rail on the gauge corner of the rail on curve. It is effective to prevent and reduce rolling contact fatigue damage by following measures, such as improving the wheel/rail shape matching, and guaranteeing the wheel/rail interface locating on the rail tread center position, and strengthening the railway maintenance, and reasonable preventive grinding and corrective grinding for rails, and strict executing the system that rail grading use, the heat-treated rails should be used on small curve radius and heavy-load railway.
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Nazaretov, A. A. "Experimental studies of sound pressure levels at the workplaces of operators of small-scale mechanization equipment when grinding rails." Herald of the Ural State University of Railway Transport, no. 3 (2021): 109–15. http://dx.doi.org/10.20291/2079-0392-2021-3-109-115.
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Intensive wear of rails in curves significantly reduces their service life, reduces the efficiency of operational work. A promising direction in solving this problem is the technology of rail grinding, which allows mechanical processing of the rail head without dismantling them in the conditions of a railway track. The article presents the results of studies of the noise impact on track workers when grinding rails by means of small mechanization-a rail-grinding machine SH-1, a grinding machine 2152D and a manual machine for grinding rails MRSH3. The analysis of various layouts of rail grinding machines, their features, technical characteristics and octave levels of sound pressure when these machines are running at idle and under load was carried out. According to the results of experimental studies, graphical dependences of the sound pressure levels of rail grinding machines are constructed, the excess of the noise level over the permissible sanitary standards in the area of rail grinding by means of small mechanization is revealed.
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Sung, Deok-Yong, and Sung-Cheon Han. "Fatigue life evaluation of continuous welded rails on concrete slab track in Korea high-speed railway." Advances in Structural Engineering 21, no. 13 (March 15, 2018): 1990–2004. http://dx.doi.org/10.1177/1369433218762501.
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There is a rapidly increasing demand for continuous welded rails. Continuous welded rails provide a more suitable installation on concrete slab tracks and more rapid and smooth movement and reduce overall maintenance cost. During the relatively short period in which concrete slab tracks have been used in Korea, there has been no documented case of rail fracture caused by repeated loading. This makes the evaluation of rail fatigue life using field data more difficult. In this study, the rail bending stress developed during high-speed train operation is obtained through analysis of vehicle–track interaction, and the correlation is analyzed by performing multiple regression analysis on train speed and rail surface irregularities. Equations for predicting the rail bending stress with regard to train speed and rail surface irregularity were derived. The effects of vehicle speed, track support stiffness, and fracture probability on the fatigue life of continuous welded rails on a concrete slab track in Korea high-speed railway were analyzed.
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Rathod, Chandrahas, David Wexler, Vladimir Luzin, Paul Boyd, and Manicka Dhanasekar. "A Neutron Diffraction Investigation of Residual Stresses in Rail Ends after Severe Deformation of Rail Surfaces." Materials Science Forum 777 (February 2014): 213–18. http://dx.doi.org/10.4028/www.scientific.net/msf.777.213.
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Insulated rail joints (IRJs) are a primary component of the rail track safety and signalling systems. Rails are supported by two fishplates which are fastened by bolts and nuts and, with the support of sleepers and track ballast, form an integrated assembly. IRJ failure can result from progressive defects, the propagation of which is influenced by residual stresses in the rail. Residual stresses change significantly during service due to the complex deformation and damage effects associated with wheel rolling, sliding and impact. IRJ failures can occur when metal flows over the insulated rail gap (typically 6-8 mm width), breaks the electrically isolated section of track and results in malfunction of the track signalling system. In this investigation, residual stress measurements were obtained from rail-ends which had undergone controlled amounts of surface plastic deformation using a full scale wheel-on-track simulation test rig. Results were compared with those obtained from similar investigations performed on rail ends associated with ex-service IRJs. Residual stresses were measured by neutron diffraction at the Australian Nuclear Science and Technology Organisation (ANSTO). Measurements with constant gauge volume 3x3x3 mm3 were carried in the central vertical plane on 5mm thick sliced rail samples cut by an electric discharge machine (EDM). Stress evolution at the rail ends was found to exhibit characteristics similar to those of the ex-service rails, with a compressive zone of 5mm deep that is counterbalanced by a tension zone beneath, extending to a depth of around 15mm. However, in contrast to the ex-service rails, the type of stress distribution in the test-rig deformed samples was apparently different due to the localization of load under the particular test conditions. In the latter, in contrast with clear stress evolution, there was no obvious evolution of d0. Since d0 reflects rather long-term accumulation of crystal lattice damage and microstructural changes due to service load, the loading history of the test rig samples has not reached the same level as the ex-service rails. It is concluded that the wheel-on-rail simulation rig provides the potential capability for testing the wheel-rail rolling contact conditions in rails, rail ends and insulated rail joints.
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Mandal, Nirmal Kumar. "Ratchetting damage of railhead material of gapped rail joints with reference to free rail end effects." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 231, no. 2 (August 4, 2016): 211–25. http://dx.doi.org/10.1177/0954409715625361.
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Free ends of insulated rail joints occur because gaps between the rails and endposts can be created due to pull-apart problems as the rails contract longitudinally in winter and by degradation of railhead material. Dynamic behaviour of gapped rail joints changes adversely compared to that of insulated rail joints. Thus, material degradation and damage of gapped rail joint components such as rail ends, joint bars, etc. are accelerated. Only limited literatures are available addressing the free end of rail effects at rail joints, targeting stress and pressure distributions in the vicinity of the rail joints. To understand clearly the material degradation and delamination process of gapped rail joints, a thorough analysis of failure of both insulated rail joints and gapped rail joints and subsequent damage of the railhead material is necessary to improve the service life of these joints. A new three-dimensional finite element analysis is carried out in this paper to assess damage to railhead material when gapped rail joints form. Both narrow (5 mm) and wide (10 mm) gaps are considered, using a peak vertical pressure load of 2500 MPa applied cyclically at one rail end, forming vertical impacts. Stress distributions and plastic deformations in the vicinity of gapped rail joints are quantified using finite element analysis data and compared with that of the insulated rail joints to show the effects of free rail ends. Residual stress and strain distributions indicate the damage to the railhead material. Equivalent plastic strain (PEEQ) quantifies the progressive damage to the railhead material at the rail ends. The free end of rail effects can be further illustrated by comparing PEEQ for insulated rail joints and gapped rail joints. The railhead material of 5 and 10 mm gapped rail joints is more sensitive to permanent deformation compared to that of the corresponding insulated rail joints. Therefore, free rail end joints pose an increased potential threat to rail operations in relation to crack initiation, damage and premature failure of railhead material.
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Luzin, Vladimir, C. Rathod, D. Wexler, Paul Boyd, and Manicka Dhanasekar. "Residual Stresses in Rail-Ends from the in-Service Insulated Rail Joints Using Neutron Diffraction." Materials Science Forum 768-769 (September 2013): 741–46. http://dx.doi.org/10.4028/www.scientific.net/msf.768-769.741.
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Insulated rail joints (IRJs) are an integral part of the rail track signaling system and pose significant maintenance and replacement costs due to their low and fluctuating service lives. Failure occurs mainly in rail head region, bolt- holes of fishplates and web-holes of the rails. Propagation of cracks is influenced by the evolution of internal residual stresses in rails during rail manufacturing (hot-rolling, roller-straightening, and head-hardening process), and during service, particularly in heavy rail haul freight systems where loads are high. In this investigation, rail head accumulated residual stresses were analysed using neutron diffraction at the Australian Nuclear Science and Technology Organisation (ANSTO). Two ex-service two head-hardened rail joints damaged under different loading were examined and results were compared with those obtained from an unused rail joint reference sample in order to differentiate the stresses developed during rail manufacturing and stresses accumulated during rail service. Neutron diffraction analyses were carried out on the samples in longitudinal, transverse and vertical directions, and on 5mm thick sliceed samples cut by Electric Discharge Machining (EDM). For the rail joints from the service line, irrespective of loading conditions and in-service times, results revealed similar depth profiles of stress distribution. Evolution of residual stress fields in rails due to service was also accompanied by evidence of larger material flow based on reflected light and scanning electron microscopy studies. Stress evolution in the vicinity of rail ends was characterised by a compressive layer, approximately 5 mm deep, and a tension zone located approximately 5- 15mm below the surfaces. A significant variation of d0 with depth near the top surface was detected and was attributed to decarburization in the top layer induced by cold work. Stress distributions observed in longitudinal slices of the two different deformed rail samples were found to be similar. For the undeformed rail, the stress distributions obtained could be attributed to variations associated with thermo-mechanical history of the rail.
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Saravana Kumar, M. N., and R. Murugan. "Analysis of Inductance Gradient and Current Density Distribution Over Different Cross-section of Rails." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 2 (April 1, 2018): 723. http://dx.doi.org/10.11591/ijece.v8i2.pp723-729.
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In a rail gun system the armature accelerated due to the Lorentz force caused by the current which is diffused in to the rails. The entire system depends on the inductance gradient of the rail which is directly connected to the accelerating performance and efficiency of railgun. Hence, the exact analysis of inductance gradient is extremely significant for the railgun design. Since short duration of current pulse is applied to the rails determination of inductance gradient is very difficult. The inductance gradient varies with the geometric dimensions of the rails and armature. And it can be calculated with analytical method and numerical methods. In this paper inductance gradient of the rail has been computed and compared with the different rail cross-sectional models using Ansoft Maxwell Eddy current solver uses finite element technique to calculate the field distribution in a space. The current density, magnetic flux density, repulsive force acting on the rails also computed to analyze the performance of rail gun.
23
Wei, Kai, Xin Xiao, and Yu De Xu. "Rail Pre-Grinding on Shanghai-Nanjing PDL and its Effect on Wheel-Rail Contact Geometry." Advanced Materials Research 779-780 (September 2013): 660–63. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.660.
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The paper tests the rail profiles of Shanghai-Nanjing PDL after its rail pre-grinding. The grinding values are counted, which shows that the grinding mainly occurs on the inner side of rail top, ranging from 0 to 1.26mm. Wheel-Rail Contact Geometry is also analyzed. Results shows that after pre-grinding, the wheel-rail contact points concentrate to the center of rail top, and it is good for rail wear control. But the rolling radius difference decreases and it weakens the rails ability of return the wheels position.
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Oh, Jeong Seok, Chun Hong Park, and Ji Hun Jeong. "Measuring the Rail Profiles of a Long Hydrostatic Guideway in a Precision Roll Lathe." Key Engineering Materials 613 (May 2014): 392–400. http://dx.doi.org/10.4028/www.scientific.net/kem.613.392.
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A system for measuring the rail profiles of a long hydrostatic guideway is proposed and applied to a precision roll lathe. The rail profiles, consisting of rail form errors and a parallelism error, are measured with four capacitive probes placed on the two rail surfaces, and a laser interferometer with angular optics. The form error of each rail is measured using a mixed sequential two-probe method, while the parallelism error between the rails is measured with two opposing capacitive probes. To eliminate the necessity for additional guidance mechanisms, theprobe table is guided by air bearings and the rails being measured. To verify the measurement results, two self-verification techniques are suggested and tested. Firstly, the linear motion errors of the probe table on the two rails are compared, yielding a difference of 0.79 μm in 2σ. Secondly, the sum of the rail form errors is compared with the slope-removed sum of the two capacitive probes used for the parallelism measurement, yielding a difference of 0.81 μm in 2σ. According to the self-verification results, the accuracy of the proposed measurement method is about 1 μm for a rail length of 2,825 mm.
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Kumar, M. N. Saravana, R. Murugan, and Poorani Shivkumar. "Inductance gradient and current density distribution for T-shaped convex and concave rail cross-sections." International Journal of Engineering & Technology 7, no. 1.8 (March 1, 2018): 237. http://dx.doi.org/10.14419/ijet.v7i1.9273.
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Rectangular rail was the most widely used cross section shape for the rail gun electromagnetic launching (EML) system. Based on sector assimilation, the rail gun key parameter especially current density (J) and inductance gradient (L’) greatly affected. J decides the efficiency of EML and L’ decides the force acting on the projectile of EML. So, it is mandatory to look upon the sector assimilation of rails. In this paper T shape convex and concave shape rail cross section is proposed and rail gun key design parameters are calculated by varying its dimensions using Ansoft Maxwell 2-D eddy current solver which uses finite element analysis technique to calculate these parameters. The performance of rail gun discussed using the obtained values and it has been observed and that the compared with other considered rail geometries, the T-shaped concave model shows more impact on inductance value which causes uniform current density distribution over the rails.
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Makowski, Jacek, Łukasz Stolarczyk, and Paweł Muzolf. "Calculation of section modulus and moments of inertia of the 60E1 rail profile due to its head cross-section change." WUT Journal of Transportation Engineering 124 (March 1, 2019): 99–114. http://dx.doi.org/10.5604/01.3001.0013.6815.
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The paper presents the theoretical foundations regarding the operational wear of rail heads. Rail, which constitute the basic element of the railway track, among others, guides the wheel in a lateral direction as well as enables a safe operation of rail vehicles. The criteria for the interaction of vehicles with the railway surface are described and the issues of interaction of the rail vehicle wheel with the rail is described. In the further part of the work an analysis of the influence of rail head wear of the 60E1 rail profile on the value of the moment of inertia Ix and sectional modulus Wx of this profile was carried out. The analysis was conducted on real, previously prepared samples of 60E1 operated rails. The methodology for calculating the geometric characteristics of cross-sectional characteristics of worn rails has been proposed using the Autodesk Autocad (Computer Aided Design software). The obtained values of moments of inertia and sectional modulus were compared with theoretical formulas described in the literature.
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Gallou, M., B. Temple, C. Hardwick, M. Frost, and A. El-Hamalawi. "Potential for external reinforcement of insulated rail joints." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 3 (December 22, 2016): 697–708. http://dx.doi.org/10.1177/0954409716684278.
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This paper aims to investigate the alternative ways of reducing the deterioration and failure of insulated rail joints of railway tracks. Joints deteriorate faster than rails due to the presence of structural discontinuity. This weakness results in extra displacement due to the applied load and dynamic force that results as a consequence. Overtime, this situation worsens as the impacts and applied stresses damage and soften the ballast and the supporting subgrade under the joint. This study initially presents a static finite element model designed to simulate the mechanics of insulated rail joints, and then a comparison is made between the plain rail and a suspended insulated rail joint under various support stiffnesses. The product design options of the reinforced insulated rail joints are then chosen as input variables of the model. The results of the model are compared with the field and laboratory data acquired via the Video Gauge, which is a new high-resolution optical measurement technique. The results show that the use of strap rails or more robust I-beam sections in the vicinity of the insulated rail joint to stiffen the support structure can significantly reduce the displacement and the subsequent dip angle seen in an insulated rail joint. This potentially presents a means of improving the behaviour of the insulated rail joints. Their impact becomes more significant for soft support conditions. Although these results are indicative of new conditions for insulated rail joints, the field measurements indicate that the magnitude of deflection of insulated rail joints is a result of the structural discontinuity of the rails, the dynamic P2 force, the wheel condition, the degraded ballast and it significantly increases with time under repeated load. Thus, it is recommended that a careful field implementation and testing will indicate the effect of an external enhancement on the timely degradation of insulated rail joints.
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Guo, Yanbin, Lulu Huang, Yingbin Liu, Jun Liu, and Guoping Wang. "Establishment of the Complete Closed Mesh Model of Rail-Surface Scratch Data for Online Repair." Sensors 20, no. 17 (August 21, 2020): 4736. http://dx.doi.org/10.3390/s20174736.
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Rail surface scratching occurs with increasing frequency, seriously threatening the safety of vehicles and humans. Online repair of rail-surface scratches on damaged rails with scratch depths >1 mm is of increased importance, because direct rail-replacement has the disadvantages of long operation time, high manpower and high material costs. Advanced online repair of rail-surface scratch using three-dimensional (3D) metal printing technology such as laser cladding has become an increasing trend, desperately demanding a solution for the fast and precise establishment of a complete closed mesh model of rail-surface scratch data. However, there have only been limited studies on the topic so far. In this paper, the complete closed mesh model is well established based on a novel triangulation algorithm relying on the topological features of the point-cloud model (PCM) of scratch-data, which is obtained by implementing a scratch-data-computation process following a rail-geometric-feature-fused algorithm of random sample consensus (RANSAC) performed on the full rail-surface PCM constructed by 3D laser vision. The proposed method is universal for all types of normal-speed rails in China. Experimental results show that the proposed method can accurately acquire the complete closed mesh models of scratch data of one meter of 50 Kg/m-rails within 1 min.
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Kuznetsova, N. V., and E. A. Sidorova. "Features of the influence of intermediate rail fastenings on the operational durability of rails." VNIIZHT Scientific Journal 80, no. 4 (September 1, 2021): 201–8. http://dx.doi.org/10.21780/2223-9731-2021-80-4-201-208.
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Heat-strengthened rails of the R65 type are the main type of rails used on the railway network of Russian Railways. Reducing the number of cropped and acutely defective rails is possible due to the rational use of the design features of intermediate rail fasteners and their current content.The article presents study results of the stiffness influence of intermediate fasteners on the operational durability of rails. The general statistics of the use of various types of intermediate rail fastenings on the network of Russian railways is considered. The main results of previously published studies on the effect of the stiffness of intermediate rail fasteners on the accumulation of contact fatigue damage in rails are briefly presented.Calculations of the accumulation of contact-fatigue damages in rails, carried out by the authors, are based on the data on the vertical and horizontal transverse stiffness of intermediate rail fastenings obtained from the results of bench tests. Calculations of the accumulation of contact-fatigue damage were carried out using the “Universal Mechanism” software package. In the process of modeling, four types of intermediate rail fasteners were considered: ARS-4, ZhBR-65Sh, ZhBR-65PShM and W-30. Calculation results were obtained for a curve with a radius of 650 m on a continuous welded track section.
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Inozemtsev, Vitaliy, Aleksey Popov, Anatoliy Kul'kov, and Anton Korytov. "PROFILING OF RAILWAY RAILS ON RAIL MILLING MACHINES." Transport engineering 2022, no. 11 (November 10, 2022): 39–51. http://dx.doi.org/10.30987/2782-5957-2022-11-39-51.
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The study objective is to increase the productivity of restoring rail profiles. The paper is devoted to the solution of the problem to determine thermal force, vibro-acoustic and energy parameters of milling machining of rail steel in various conditions. The computational and analytical method of research, express diagnostics are used. The novelty is in the proposed improved technology of rail reprofiling. The following results are obtained: it is found that the most productive and effective method of rail reprofiling in stationary conditions is milling on special rail milling machines; the main directions of increasing the machinability of rail steel are determined, which allows the development of induction heating technology for softening the surface defective metal layer of the rail head. Conclusion: the range of rational cutting modes of rail steel with thermal annealing are found.
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Yuan, Jun, Zhen Yu Han, Yong Deng, and Da Wei Yang. "Austenite Grain Evolution Mechanism of High Carbon Rail Based on Thermal Technology." Key Engineering Materials 837 (April 2020): 74–80. http://dx.doi.org/10.4028/www.scientific.net/kem.837.74.
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In view of the special requirements of rails to ensure the safe and stable operation of Railways in China, the formation characteristics of austenite grains in high carbon rail are revealed through industrial exploration, the process of industrial rail heating and rolling is simulated, innovative experimental research methods such as different heating and heat treatment are carried out on the actual rails in the laboratory. Transfer characteristics of austenite grain size, microstructures and key properties of high carbon rail during the process are also revealed. The results show that the austenite grain size of industrial produced U75V rail is about 9.0 grade. When the holding temperature is increased from 800 C to 1300 C, the austenite grain size of high carbon rail steel decreases, the austenite grain are gradually coarsened, and the tensile strength increases slightly. The tensile strength is affected by the heating temperature. With the increase of heating temperature, the elongation and impact toughness of high carbon rail decrease. The heating temperature of high carbon rail combined with austenite grain size shows that the heating temperature has a great influence on austenite grain size, and has the most obvious influence on the toughness of high carbon rail.
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Seo, Jung Won, Seok Jin Kwon, Hyun Kyu Jun, and Dong Hyung Lee. "Microstructure Features and Contact Fatigue Crack Growth on Rail." Materials Science Forum 654-656 (June 2010): 2491–94. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2491.
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Rolling Contact Fatigue (RCF) damage on the surface of rails such a head check, squats is a growing problem. Since rail fractures can cause derailment with loss of life and property, the understanding of rail fracture mechanism is important for reducing damages on the rail surface. In this study, we have investigated RCF damage, fatigue growth and fracture surface morphology on the surface of broken rail using failure analysis and finite element (FE) analysis. The investigation indicates that the crack grows at about 20° to the depth of 8mm from the surface and branches into two cracks. One crack propagates downward at about 47°, the other propagates upward. Since the crack growth rate of the downward crack was faster than that of upward crack, rail eventually was broken. Since the downward branches lead to fracture of the rail, they are more dangerous to the integrity of rails. It has been observed that White Etching Layer (WEL) occurs within the surface of broken rail. It was found that the fatigue crack initiation and propagation was accelerated by WEL.
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Wang, Pu, Shuguo Wang, and Daolin Si. "Numerical prediction of rail wear development in high-speed railway turnouts." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 10 (January 22, 2020): 1299–318. http://dx.doi.org/10.1177/0954409719896440.
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Wear of rails in turnouts is a common problem during the operation of high-speed railways. It can seriously affect the running safety of trains and the service lives of wheels and turnout rails. In this study, a numerical prediction model for rail wear development in high-speed railway turnouts was established. According to the material wear theory developed by Archard, the wear depth distribution in the wheel–rail contact patch was calculated based on a vehicle–turnout coupling dynamics simulation and wheel–rail rolling contact analysis. For the dynamics model, various components of the vehicle and complex nonlinear interactions between the components were simulated in detail to guarantee consistency with reality. The combination relationship of the switch and stock rails and the irregular and variable cross-sections of the rails in the switch panel of the turnout were considered. Spatial interpolation was used to achieve three-dimensional transitions between adjacent irregular cross-sections to model the compromised rails in the turnout. In addition, the stiffness and damping characteristics of the track in the turnout zone were taken into account. The rail wear rates for every characteristic section of the switch panel were calculated by the superposition model for rail profile wear. An adaptive-step algorithm was adopted in the iterative computations to update the rail profiles for every characteristic section position, which could reduce the cumulative errors and effectively improve the stability and reliability of the numerical model. Finally, case studies were conducted to investigate the wear developments of the switch and stock rails of high-speed turnouts using the developed model. In addition, the rail wear status of turnouts in the Shanghai–Nanjing high-speed railway was measured. The numerical prediction results are consistent with those of the actual situations in the field, verifying the rationality of the established model. This work shows the potential for guiding the maintenance and optimal design of turnouts and improving the understanding of the formation mechanism and influencing factors of rail wear in turnouts.
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Noufid, Abdelhamid, Nadia Hidar, Sougrati Belattar, Mohamed Elafi, and M’barek Feddaoui. "Thermal non-destructive characterization of rail networks by using Infrared Thermography and FEM simulation." MATEC Web of Conferences 360 (2022): 00014. http://dx.doi.org/10.1051/matecconf/202236000014.
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Because of the repeated passage of trains, anomalies are created inside the rails in the form of cracks of different shapes and position. These are due essentially to the wheel – rail contact. They present a hazard causing at the final stage rail failure, train derailment and accidents. Detecting track anomalies has become a major issue for the entire rail industry around the world. This paper focuses on the degradation of rails in urban railways in terms of cracks. The purpose is to develop an approach to detect and predict rail breaks, which will optimize maintenance task. Infrared thermography was used in order to characterise the effect of a defect on the acquired thermogram. Different defects were considered by varying their size, depth and inclination angle with respect to the rail surface.
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Kosenko, Sergey, Sergey Akimov, and Pavel Surovin. "Technology of rail replacement at end stresses." MATEC Web of Conferences 216 (2018): 01002. http://dx.doi.org/10.1051/matecconf/201821601002.
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The paper focuses on topical issues relating to the maintenance of buffer spans and temporarily repaired sections of continuous welded rail (CWR) tracks. The paper is aimed at developing and studying the feasibility of a technology for replacing temperature-stressed continuous welded rails. For the purposes of this research, the analytical modeling method is used. A design model for moving the end of the stressed rail to the side is presented. Equations of deflections and bending moments arising when the rail is bent to the rated value were derived. Stresses on the rail bending length were determined and compared with the maximum allowable ones. A resource-saving technology has been developed for replacing temperature-stressed buffer rails of a CWR track using intermediate rail fastening Vossloh W-30.
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Mao, Xin, and Gang Shen. "A design method for rail profiles based on the geometric characteristics of wheel–rail contact." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 5 (July 10, 2017): 1255–65. http://dx.doi.org/10.1177/0954409717720346.
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Designing a proper rail profile carries more significance than designing a wheel profile because of the amount of work and cost involved in the maintenance of rails. A better rail profile will not only help to ensure achieving the desired dynamic performance of rail vehicles but it also extends the service life of rails. This paper presents a unique design method for the design of rail profiles based on the given geometric contact characteristics. The proposed method utilizes a given wheel profile and two typical functions respectively to set the main design targets. The first function is the rolling radii difference and the second one is the contact angle difference. Wheel–rail contact distribution is chosen as the secondary target to prevent stress concentration and the associated fatigue failure. With certain assumptions, the solution process becomes a reverse designed one, which can be solved by using proper discrete numerical methods. Two examples of rail profile designs have been discussed in detail for rigid and independent wheelsets.
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Ling, Liang, Jian Han, Xinbiao Xiao, and Xuesong Jin. "Dynamic behavior of an embedded rail track coupled with a tram vehicle." Journal of Vibration and Control 23, no. 14 (November 15, 2015): 2355–72. http://dx.doi.org/10.1177/1077546315616521.
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This paper presents an investigation into the dynamic behavior of an embedded rail track coupled with a tram vehicle in time domain. A new designed embedded rail track structure firstly introduced into the Chinese tramways is described and the results of vibration tests of the embedded rail track (ERT) and another fastened slab track (FST) are discussed. A three-dimensional (3D) dynamic model of a tram vehicle coupled with an embedded rail track was developed on the basis of the multi-body dynamics approach and the finite element method. In the model, the tram vehicle was modeled as a multi-body system. The embedded rail track was modeled as a two layer system consisting of two rails, filling material, slabs, and adjustment layer beneath slabs. The rails were treated as Timoshenko beams with continuous elastic supports, in which the modal superposition method was used to reduce the order of the partial differential equations of beams. Continuous viscoelastic elements were used to represent the filling material and rail pad that connecting the rails and the slabs. The concrete slabs were modelled using the 3D finite element method, while the modal superposition method was adopted to improve the computational efficiency. Uniformly viscoelastic elements were introduced to model the elastic layer beneath the concrete slabs. The proposed model was then applied to compare the dynamic response of the innovative embedded rail track with respect to a conventional fastened slab track. The numerical results indicate that the innovative embedded rail track has advantages over the fastened slab track for its potentialities to reduce the dynamic wheel/rail force, the vibration level and deformation of the track parts, and the track defects and damages.
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Shi, Shengrun, Zhiyuan Han, Zipeng Liu, Patrick Vallely, Slim Soua, Sakdirat Kaewunruen, and Mayorkinos Papaelias. "Quantitative monitoring of brittle fatigue crack growth in railway steel using acoustic emission." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 4 (June 1, 2017): 1211–24. http://dx.doi.org/10.1177/0954409717711292.
Full textAbstract:
Structural degradation of rails will unavoidably take place with time due to cyclic bending stresses, rolling contact fatigue, impact and environmental degradation. Rail infrastructure managers employ a variety of techniques and equipment to inspect rails. Still tens of rail failures are detected every year on all major rail networks. Inspection of the rail network is normally carried out at night time, when normal traffic has ceased. As the implementation of the 24-h railway moves forward to address the increasing demand for rail transport, conventional inspection processes will become more difficult to implement. Therefore, there is an obvious need to gradually replace outdated inspection methodologies with more efficient remote condition monitoring technology. The remote condition monitoring techniques employed should be able to detect and evaluate defects without causing any reduction in the optimum rail infrastructure availability. Acoustic emission is a passive remote condition monitoring technique which can be employed for the quantitative evaluation of the structural integrity of rails. Acoustic emission sensors can be easily installed on rails in order to monitor the structural degradation rate in real time. Therefore, apart from detecting defects, acoustic emission can be realistically applied to quantify damage. In this study, the authors investigated the performance of acoustic emission in detecting and quantifying damage in rail steel samples subjected to cyclic fatigue loads during experiments carried out under laboratory conditions. Herewith, the key results obtained are presented together with a detailed discussion of the approach employed in filtering noise sources during data acquisition and subsequent signal processing.
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Gertsyk, Svetlana, and Natalya Volgina. "Causes of destruction of continuous welded rail tracks." MATEC Web of Conferences 329 (2020): 03046. http://dx.doi.org/10.1051/matecconf/202032903046.
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The main causes of destruction of continuous welded rail tracks, the main types of their destruction and the causes of their occurrence are considered. The technologies for the manufacture of rails are analyzed, including heat treatment along the entire length of the rail, treatment of the ends of the rail, surface hardening and anti-flake treatment. To increase the durability of rail tracks, a number of measures have been proposed.
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Prokof’iev, O., R. Gubatyuk, S. Rymar, V. Sydorets, and Valery Kostin. "Inductor for Uniform Bulk Heat Treatment of Welded Butt Joints of Railway Rails." Solid State Phenomena 313 (January 2021): 72–81. http://dx.doi.org/10.4028/www.scientific.net/ssp.313.72.
Full textAbstract:
To improve the structure of metal in welded butt joints of railway rails produced by flash-butt welding and increase the reliability of butt joints, it is advisable to carry out their induction heat treatment using high-frequency currents. Solving the problem of a uniform bulk heating of weld metal of railway rails in a narrow area during its heat treatment remains an urgent task. The work describes the principle of designing an inductor without magnetic cores for carrying out a uniform bulk heat treatment of welded butt joints of railway rails for realization of favorable phase transformations of metal and normalization of its structure. The principle is based on the physical laws of propagation of electromagnetic fields and electric currents in the inductor and a rail. Based on the carried out investigations, an inductor was designed that has a variable shape along the perimeter of a rail and a variable distance from it, as well as a partial splitting of the inductor busbar for current parallelization, which provides a uniform bulk heating of a rail butt joint. Splitting of the inductor busbar allowed adjusting the propagation of currents in the inductor and a rail in such a way as to avoid overheating of a rail in its particular areas without a significant increase in the distance between the inductor and a rail, and respectively without a significant increase in the reactive power of the “inductor-product” system. The carried out experiments on heating the welded butt joint of a rail by the designed inductor showed the indices of uniformity and rate of its bulk heating, which are acceptable for heat treatment of rails both on the surface as well as in the depth of a rail in a narrow heating zone with providing the required temperature levels.
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Prokof’iev, O., R. Gubatyuk, S. Rymar, V. Sydorets, and Valery Kostin. "Inductor for Uniform Bulk Heat Treatment of Welded Butt Joints of Railway Rails." Solid State Phenomena 313 (January 2021): 72–81. http://dx.doi.org/10.4028/www.scientific.net/ssp.313.72.
Full textAbstract:
To improve the structure of metal in welded butt joints of railway rails produced by flash-butt welding and increase the reliability of butt joints, it is advisable to carry out their induction heat treatment using high-frequency currents. Solving the problem of a uniform bulk heating of weld metal of railway rails in a narrow area during its heat treatment remains an urgent task. The work describes the principle of designing an inductor without magnetic cores for carrying out a uniform bulk heat treatment of welded butt joints of railway rails for realization of favorable phase transformations of metal and normalization of its structure. The principle is based on the physical laws of propagation of electromagnetic fields and electric currents in the inductor and a rail. Based on the carried out investigations, an inductor was designed that has a variable shape along the perimeter of a rail and a variable distance from it, as well as a partial splitting of the inductor busbar for current parallelization, which provides a uniform bulk heating of a rail butt joint. Splitting of the inductor busbar allowed adjusting the propagation of currents in the inductor and a rail in such a way as to avoid overheating of a rail in its particular areas without a significant increase in the distance between the inductor and a rail, and respectively without a significant increase in the reactive power of the “inductor-product” system. The carried out experiments on heating the welded butt joint of a rail by the designed inductor showed the indices of uniformity and rate of its bulk heating, which are acceptable for heat treatment of rails both on the surface as well as in the depth of a rail in a narrow heating zone with providing the required temperature levels.
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Qian, WJ, ZQ Huang, H. Ouyang, GX Chen, and HJ Yang. "Numerical investigation of the effects of rail vibration absorbers on wear behaviour of rail surface." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, no. 3 (June 27, 2018): 424–38. http://dx.doi.org/10.1177/1350650118785061.
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Rail corrugation refers to the periodic wear of the top working surfaces of rails. This problem has plagued the railway industry over a hundred years. In the present paper, the effects of rail vibration absorbers on wear behaviour of the rail surface have been studied. The dynamic model of a wheel–rail–absorber system is established. The friction contact coupling between the wheel and the rail are fully considered in this model. A wear model, in which the mass loss of unit area in contact patch is proportional to frictional work per unit area between the wheel and the rail, is developed to analyse the wear behaviour of the rail surface. Numerical results show that the saturated creep force-induced self-excited vibration of the wheel–rail system can result in short pitch rail corrugation on the rail surface. The maximum wear depth occurs at the positions close to mid-span of each sleeper bay. After the installation of rail vibration absorbers, the formation of short pitch rail corrugation can be suppressed effectively, and the wear on the rail surface becomes uniform and the growth rate of rail corrugation reduces considerably. Increasing the connection damping between the absorber and the rail web is beneficial to preventing the formation of short pitch rail corrugation.
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Zhu, Liqiang, Xiangyu Duan, and Zujun Yu. "On the Identification of Elastic Moduli of In-Service Rail by Ultrasonic Guided Waves." Sensors 20, no. 6 (March 22, 2020): 1769. http://dx.doi.org/10.3390/s20061769.
Full textAbstract:
Non-destructive rail testing and evaluation based on guided waves need accurate information about the mode propagation characteristics, which can be obtained numerically with the exact material properties of the rails. However, for rails in service, it is difficult to accurately obtain their material properties due to temperature fluctuation, material degradation and rail profile changes caused by wear and grinding. In this study, an inverse method is proposed to identify the material elastic constants of in-service rails by minimizing the discrepancy between the phase velocities predicted by a semi-analytical finite element model and those measured using array transducers attached to the rail. By selecting guided wave modes that are sensitive to moduli but not to rail profile changes, the proposed method can make stable estimations for worn rails. Numerical experiments using a three-dimensional finite element model in ABAQUS/Explicit demonstrate that reconstruction accuracies of 0.36% for Young’s modulus and 0.87% for shear modulus can be achieved.
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Potapov, Dmitry, Volodymyr Vitolberg, Danylo Shumyk, Viacheslav Ovcharenko, and Viktor Bulgakov. "Reused rails for underground systems." MATEC Web of Conferences 230 (2018): 01013. http://dx.doi.org/10.1051/matecconf/201823001013.
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The structural components of the rail track, including rails, deteriorate in operation. However, some of them retain their operational characteristics and can be reused. This practice has found wide application on Ukrainian railways and shown a lot of self-evident advantages, among which the basic one is a rational use of material and technical means. Besides, development of a used rail system for underground railways may also optimize the track facility system for such specific conditions. The article presents results of the research into the change of the crumbling depth on the roll surface (the main rail defects of underground railways); it allowed the authors to conclude about the possibility to reuse rails for underground systems. Moreover, assessment of interacting forces in the wheel/rail system and the crumbling volume made it possible to determine rational application for used rails. The proposed system takes into account all the features of operating the railway track in underground systems, and also allows more efficient use of the residual rail resource without reducing the necessary level of traffic safety.
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Kapitsa, Mikhail, Evgen Mikhailov, Sergii Kliuiev, Stanislav Semenov, and Maksim Kovtanets. "Study of rail vehicles movement characteristics improvement in curves using fuzzy logic mechatronic systems." MATEC Web of Conferences 294 (2019): 03019. http://dx.doi.org/10.1051/matecconf/201929403019.
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The article deals with the effectiveness of reducing the level of force interaction of the rail vehicle wheels with rails in curved sections of the track through the use of mechatronic position control systems for wheel pairs in the rail gauge in the horizontal plane. The approaches to the creation of such a mechatronic system operating on the principles of fuzzy logic are described. To determine the angles of attack of wheels on the rails, it was proposed to use the acoustic emission indicators of the contact of the wheel with the rail. To determine the direction of curvature of the rail track, it is advisable to use data from navigation systems. The study of the dynamics of the rail vehicle during the passage of a curved section of the track in real time was carried out using the Matlab/Simulink software package. The proposed mechatronic control system for the position of the wheel sets in the horizontal plane allows to ensure their optimal installation under various driving conditions in the rail gauge. This makes it possible to minimize the angles of attack of the wheels and reduce the forces of the horizontal interaction of the wheels with the rails.
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Olofsson, U., and R. Nilsson. "Surface cracks and wear of rail: A full-scale test on a commuter train track." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 216, no. 4 (July 1, 2002): 249–64. http://dx.doi.org/10.1243/095440902321029208.
Full textAbstract:
Damage mechanisms such as surface cracks and wear on a rail can reduce the service life of a railway track. The purpose of this investigation was to study the development of these two damage mechanisms on new and 3-year-old rails in a commuter railway track over a period of 2 years. Four curves were studied with radius between 303 and 616m. In two of the curves, two different kinds of rail steel grade (UIC 900A grade with ultimate strength 900N/mm2 and UIC 1100 grade with ultimate strength 1100N/mm2) were used in each curve. In the other two curves, only the lower-strength rail was used. Four pieces of new rail, each 20m long, were inserted in the two curves with both UIC 900A and UIC 1100 grade rail. Lubrication was applied on the high rail of one of the curves with both UIC 900A and UIC 1100 grade rail and on one of the curves with only UIC 900A grade rail. The two remaining curves were not lubricated. Surface cracks in the form of headchecks could be noted on the surface of the new 1100 grade rails after 1 month of traffic. By contrast, the surface of the UIC 900A grade rails showed visible surface cracks in only two of four curves and that after approximately 2 years of traffic. Both materials seemed to be similarly sensitive to crack initiation but the 1100 grade rail was more sensitive to crack propagation and also more sensitive to the formation of headcheck cracks. Lubrication, as expected, reduced the profile change. A less expected outcome was that lubrication also reduced the rate of crack propagation; however, the lubricated UIC 1100 grade rail was as sensitive to crack initiation as the unlubricated UIC 1100 grade rail. By comparing the wear depth in the headcheck zone with the crack length, equilibrium between these two damage mechanisms was found for the lubricated UIC 1100 grade rail. Both the crack length and the wear depth showed low values. By using a lubricant with friction modifiers the stresses was low enough to prevent crack propagation; at the same time, the rail was hard enough to reduce the wear rate. This is probably the most favourable state in terms of rail maintenance cost.
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Pavlova, Kristina, Todor Stoilov, and Krasimira Stoilova. "Bi-Level Model for Public Rail Transportation under Incomplete Data." Cybernetics and Information Technologies 17, no. 3 (September 1, 2017): 75–91. http://dx.doi.org/10.1515/cait-2017-0031.
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Abstract The increase of the utilization of public rail transportations is searched in directions for redistribution of the passenger travels between rail and bus transportation. The rail transport benefits by redistribution of the transportation flows on paths, predominantly supported by rails. The redistribution of the transportation is formalized by bi-level optimization problem. The upper level optimization estimates the maximal flow, which can be transported through a transportation network, supported both by bus and rail transports. The lower level optimization gives priority to the rail transport by decreasing the costs of flow distribution, using rail transport. This bi-level optimization problem was applied for the case of optimization of the rail exploitation in Bulgaria, defining priorities in transportation of the National transport scheme.
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Guo, Yongqing, Xiaoyuan Wang, Qing Xu, Shanliang Liu, Shijie Liu, and Junyan Han. "Weather Impact on Passenger Flow of Rail Transit Lines." Civil Engineering Journal 6, no. 2 (February 1, 2020): 276–84. http://dx.doi.org/10.28991/cej-2020-03091470.
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Passenger flow prediction is important for the planning, design and decision-making of urban rail transit lines. Weather is an important factor that affects the passenger flow of rail transit line by changing the travel mode choice of urban residents. A number of previous researches focused on analyzing the effects of weather (e.g. rain, snow, and temperature) on public transport ridership, but the effects on rail transit line yet remain largely unexplored This study aims to explore the influence of weather on ridership of urban rail transit lines, taking Chengdu rail transit line 1 and line 2 as examples. Linear regression method was used to develop models for estimating the daily passenger flow of different rail transit lines under different weather conditions. The results show that for Chengdu rail transit line 1, the daily ridership rate of rail transit increases with increasing temperature. While, for Chengdu rail transit line 2, the daily ridership rate of rail transit decreases with increasing wind power. The research findings can provide effective strategies to rail transit operators to deal with the fluctuation in daily passenger flow.
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Csortos, Gabriella, Fülöp Augusztinovicz, and Péter Bocz. "Optimal operation of a rail lubrication device with respect to noise reduction and wheel/rail friction coefficient." Acta Technica Jaurinensis 14, no. 2 (May 26, 2021): 138–54. http://dx.doi.org/10.14513/actatechjaur.00592.
Full textAbstract:
During research work, three series of studies were performed to support the importance of using rail lubrication at tramway tracks in Budapest. The first task was to determine the noise reduction efficiency of automated rail lubrication: noise measurements were performed in case of lubricated rails with corrugations, non-lubricated rails with corrugations, grinded rails as well as grinded and lubricated rails. Once the conformity was determined, an additional task was to find the right lubricant. After the noise and braking effect tests of various lubricants, it was a legitimate need to determine the optimum lubricant application because the setting of the devices is based only on the experience of the Operator. Finally, the noise mitigation effect and the friction coefficient affecting the wheel/rail contact with different lubricant application settings were investigated simultaneously. It is important that the lubricant be applied in appropriate amount such that even the safe movement of the trams is guaranteed, but at the same time the noise reduction is satisfactory too. Based on the results, the authors make recommendations for the application of the rail lubrication devices.
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Атрошенко, С. А., С. С. Майер, and В. И. Смирнов. "Анализ разрушения перлитной рельсовой стали с внутренней макротрещиной." Физика твердого тела 63, no. 5 (2021): 575. http://dx.doi.org/10.21883/ftt.2021.05.50803.244.
Full textAbstract:
One of the most dangerous defects leading to transverse fractures of rails is internal transverse cracks in the rail head. In this work, a fractographic analysis of the cross-sectional surface of a rail with a transverse fatigue crack is carried out. The rail sample was taken out of work after many years of service. Microstructural analysis of the crack surface and the surrounding material shows a significant degradation of the physical and mechanical properties of the rail steel.