Journal articles: 'Longitudinal train dynamics'

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Spiryagin, Maksym, Qing Wu, and Colin Cole. "Longitudinal train dynamics." Vehicle System Dynamics 55, no. 4 (January 30, 2017): 449. http://dx.doi.org/10.1080/00423114.2017.1285510.

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Ding, Li Fen, and Ji Long Xie. "Research on the Effect of Traction Tonnage on Train Longitudinal Impact." Key Engineering Materials 450 (November 2010): 466–69. http://dx.doi.org/10.4028/www.scientific.net/kem.450.466.

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The traction tonnage has important effect on train longitudinal impact. An integrated model of train longitudinal dynamics was established based on simulation and test results. The effect of the traction tonnage on train longitudinal dynamics was investigated through modeling different types of heavy-haul trains. The model was validated by using measured longitudinal force time histories from on-track tests. Case study shows that the traction tonnage has significant influence on train longitudinal impact; Train longitudinal force increases with traction tonnage. The relationships between the maximum coupler forces (including tensile and compressive forces) and traction tonnage were obtained with the least square method for cases of train under emergency baking and release condition. The established train longitudinal dynamics model provides a platform for car body and coupler structure optimization and train control.

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Wu, Qing, Maksym Spiryagin, and Colin Cole. "Longitudinal train dynamics: an overview." Vehicle System Dynamics 54, no. 12 (September 7, 2016): 1688–714. http://dx.doi.org/10.1080/00423114.2016.1228988.

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Shi, Jin, Shujing Ren, and Mengran Zhang. "MODEL-BASED ASSESSMENT OF LONGITUDINAL DYNAMIC PERFORMANCE AND ENERGY CONSUMPTION OF HEAVY HAUL TRAIN ON LONG-STEEP DOWNGRADES." Transport 34, no. 3 (March 21, 2019): 250–59. http://dx.doi.org/10.3846/transport.2019.9043.

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Longitudinal dynamics performance and energy consumption of heavy haul train should be considered in the design of heavy haul railway profile of long-steep downgrades. A quantitative analytical tool is developed to assess the longitudinal dynamic performance and energy consumption of heavy haul trains with large axle loads on grades with different longitudinal profiles, including a longitudinal dynamic model of the train and a method of calculating the energy consumption during the operation of heavy haul train. The model is then preliminarily validated by the data of coupler force collected in two comprehensive tests. Finally, the proposed analytical tool is used to assess the designed longitudinal track profile of a long-deep downgrade segment of the central south heavy haul railway of Shanxi (China).

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Krishna, Visakh V., Mats Berg, and Sebastian Stichel. "Tolerable longitudinal forces for freight trains in tight S-curves using three-dimensional multi-body simulations." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 5 (April 16, 2019): 454–67. http://dx.doi.org/10.1177/0954409719841794.

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With the need for increasing length of freight trains, the longitudinal train dynamics and its influence on the running safety become a key issue. Longitudinal train dynamics is a complex issue with contributions from both the vehicle and the operating conditions such as infrastructure design, braking regimes, etc. Standards such as the UIC Code 530-2 and EN-15839 detail the procedure for on-track propelling tests that should be conducted to determine the running safety of a single wagon. Also, it only considers a single S-curve and specifies neighbouring wagons and buffers. Hence, the resulting longitudinal train dynamics would not be able to judge the effects of various heterogeneities in the train formation such as the adjacent wagons, buffer types, carbody torsional stiffnesses, curvatures, etc. Here, there is a potential of using three-dimensional multi-body simulations to develop a methodology to judge the running safety of a train with regard to its longitudinal dynamic behaviour, subjected to various heterogeneities. In this study, a tool based on three-dimensional multi-body simulations has been developed to provide longitudinal compressive force limits and tolerable longitudinal compressive force for wagon combinations passing through S-curves of varying curvatures, and the sensitivities of the various heterogeneities present in the train are assessed. The methodology is applied to open wagons of the ‘Falns’ type on tight S-curves by calculating the corresponding tolerable longitudinal compressive force, and the effect of various parameters on the same is discussed.

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Jackiewicz, Jacek. "Coupler force reduction method for multiple-unit trains using a new hierarchical control system." Railway Engineering Science 29, no. 2 (June 2021): 163–82. http://dx.doi.org/10.1007/s40534-021-00239-w.

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AbstractDuring traction and braking of multiple-unit trains, substantial longitudinal dynamic forces might occur in couplers due to the non-optimal distribution of traction and braking forces generated by self-propelled carriages. These dynamic forces might create shocks affecting the reduction of endurance of the weakest train structural components primarily. Thus, the overall operational safety of the train is also lowered. The purpose of the paper is to develop a new control system to supervise the activities related to the longitudinal dynamics of each train carriage in a multiple-unit train to reduce the longitudinal coupler forces acting during train traction and braking. The hierarchical structure of the control system consists of two levels. The first master level of control works like standard cruise control. However, the reduction of longitudinal coupler forces is achieved by applying a second level of slave control systems with a control configuration of feedback compensation.

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Xu, Yan, Shi Yun Zhao, and Na Na Wang. "The Influences of the Load Distribution Pattern and the Position of the Locomotive on Train Longitudinal Dynamics." Applied Mechanics and Materials 496-500 (January 2014): 1063–67. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.1063.

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According to the principle of the train longitudinal dynamics, the heavy haul longitudinal dynamics nonlinear model is established to analyze the influences of the load distribution pattern and the locomotive position on train longitudinal dynamics. The study of this paper is divided into two parts. The first, train model is composed by a locomotive and six trailers, researching the influences of the load distribution pattern on train longitudinal dynamics, the analysis results show that, the best load distribution pattern is the descending from head to tail of the train, in this case, the coupler force is minimum, and the train longitudinal dynamics is best; the second, train model is composed by two locomotives and five trailers, researching the influences of the position of the locomotive on train longitudinal dynamics. The analysis results show that, if the first locomotive is at the head of the train, then the second locomotives best position is at the end of the train, in this case, the coupler is minimum. But the train longitudinal dynamics performance is the worst with two locomotives are located in the head.

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Cruceanu, Cătălin, and Camil Ion Crăciun. "About Longitudinal Dynamics of Classical Passenger Trains during Braking Actions." Applied Mechanics and Materials 378 (August 2013): 74–81. http://dx.doi.org/10.4028/www.scientific.net/amm.378.74.

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There are presented and analyzed specific aspects regarding the main mechanic and pneumatic issues determining the in-train dynamic forces developed during braking actions. Particularities in case of passenger trains are highlighted, with the aim of proving that even in the case of short trains, fitted with UIC type P braking system, longitudinal dynamics can cause significant reactions whose effect cannot be neglected, both in terms of traffic safety and comfort. Numerical examples presented stand for this.

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Crăciun, Camil, and Cătălin Cruceanu. "Influence of resistance to motion of railway vehicles on the longitudinal trains dynamics." MATEC Web of Conferences 178 (2018): 06003. http://dx.doi.org/10.1051/matecconf/201817806003.

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Longitudinal dynamics of trains is a subject that generates discussions and views on the parameters that interfere and influence both the size of the forces and their distribution in the train body. The paper is a study to determine the influence of resistances to motion on the longitudinal dynamic forces that develop in the body of the train in the braking process. For this, a train study model of ten identical vehicles, to which the locomotive may or may not be attached, is adopted. Initially, the simulation program for the non-locomotive model is run in two variants: with and without introducing additional resistances to motion, followed by the same simulations but with the locomotive introduced and a wagon removed, thus the number of vehicles remains the same for all the cases presented.

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Choi, Don Bum, Rag-Gyo Jeong, Yongkook Kim, and Jangbom Chai. "Comparisons Between Braking Experiments and Longitudinal Train Dynamics Using Friction Coefficient and Braking Pressure Modeling in a Freight Train." Open Transportation Journal 14, no. 1 (July 30, 2020): 154–63. http://dx.doi.org/10.2174/1874447802014010154.

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Background: This paper describes the predictions and validation of the pneumatic emergency braking performance of a freight train consisting of a locomotive and 20 wagons, generally operated in Korea. It suggests the possibility of replacing the expensive and time-consuming train running tests with longitudinal train dynamic simulations. Methods: The simulation of longitudinal train dynamics of a freight train uses the time integration method of EN 14531. For reasonable simulation results, the characteristics of the train and brake equipment must be considered. For the train characteristics, specifications provided by the vehicle manufacturer are used. The braking characteristics are analyzed by friction coefficient tests and a braking pressure model. The friction coefficients of a locomotive and wagons are tested with a dynamo test bench and statistically expanded to account for variability. Freight trains should take into account the braking delay time. To reflect this in the simulation, the brake cylinder pressure pattern model uses pressures and exponential empirical equations measured at selective positions in a train of 50 vehicles. The simulation results are validated in comparison with those of the braking tests of a freight train consisting of 1 locomotive and 20 wagons. Results: The results of the longitudinal dynamics simulation show very similar results to the running test results based on the speed profile and braking distance. Conclusion: In particular, the statistical expansion method of the friction coefficient enables robust prediction of the distribution of the braking distance. The simulation can reduce or make up for costly and time-consuming repeated braking tests and reduce the risks that may arise during testing.

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Krishna, Visakh V., Daniel Jobstfinke, Stefano Melzi, and Mats Berg. "An integrated numerical framework to investigate the running safety of overlong freight trains." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 235, no. 1 (February 18, 2020): 47–60. http://dx.doi.org/10.1177/0954409720905203.

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Long freight trains up to 1500 m in length are currently not in regular operation in Europe. One of the important reasons for the same is high inter-wagon forces generated during the operation, especially when pneumatic (P-type) brake systems are used. For long trains with multiple locomotives at different positions along the train, radio communication with necessary fail-safe mechanisms can be used to apply the brakes. Long freight train operation on a given line is subjected to various attributes such as braking/traction scenarios, loading patterns, wagon geometries, brake-block materials, buffer types, track design geometries, etc., which are referred to as heterogeneities. The complex longitudinal train dynamics arising in the train due to various heterogeneities play a major role in determining its running safety. In this context, the maximum in-train force refers to the maximum force developed between any two wagons along the train during operation. The tolerable longitudinal compressive force is the maximum compressive force that can be exerted on a wagon without resulting in its derailment. Here, the authors adopt a bottom-up approach to model pneumatic braking systems and inter-wagon interactions in multibody simulation environments to study the complex longitudinal train dynamics behavior and estimate maximum in-train forces and tolerable longitudinal compressive forces, subjected to various heterogeneities. These two force quantities intend to facilitate a given freight train operation by providing guidelines regarding the critical heterogeneities, that currently limit its safe operation. In doing so, the authors propose the notion to have an operation-based approval for long freight trains using the simulations-based tool.

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Wu, Qing, Maksym Spiryagin, Peter Wolfs, and Colin Cole. "Traction modelling in train dynamics." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 4 (August 30, 2018): 382–95. http://dx.doi.org/10.1177/0954409718795496.

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This paper presents five locomotive traction models for the purpose of train dynamics simulations, such as longitudinal train dynamics simulations. Model 1 is a look-up table model with a constant force limit to represent the adhesion limit without modelling the wheel–rail contact. Model 2 is improved from Model 1 by empirically simulating locomotive sanding systems, variable track conditions and traction force reduction due to curving. Model 3 and Model 4 have included modelling of the wheel–rail contact and traction control. Model 3 uses a two-dimensional locomotive model while Model 4 uses a three-dimensional locomotive. Model 5 is based on Model 2 and developed to simulate hybrid locomotives. Demonstrative simulations are presented for the case of longitudinal train dynamics. The results show that the consideration of locomotive sanding systems, variable track conditions and traction force reduction have evident implications on the simulated traction forces. There can be up to 30% difference in the simulated traction forces. Simulated traction forces by models that consider the wheel–rail contact are about 10–15% lower than those simulated by models without consideration of the wheel–rail contact. This is mainly due to the variable friction in the wheel–rail contact and conservative traction control schemes.

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Cole, Colin, Maksym Spiryagin, and Chris Bosomworth. "Examining longitudinal train dynamics in ore car tipplers." Vehicle System Dynamics 55, no. 4 (December 15, 2016): 534–51. http://dx.doi.org/10.1080/00423114.2016.1263393.

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Cole, Colin, Maksym Spiryagin, Qing Wu, and Yan Quan Sun. "Modelling, simulation and applications of longitudinal train dynamics." Vehicle System Dynamics 55, no. 10 (June 7, 2017): 1498–571. http://dx.doi.org/10.1080/00423114.2017.1330484.

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Wu, Qing, Maksym Spiryagin, Colin Cole, Chongyi Chang, Gang Guo, Alexey Sakalo, Wei Wei, et al. "International benchmarking of longitudinal train dynamics simulators: results." Vehicle System Dynamics 56, no. 3 (September 20, 2017): 343–65. http://dx.doi.org/10.1080/00423114.2017.1377840.

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Sharma, Sunil Kumar, and Anil Kumar. "Impact of Longitudinal Train Dynamics on Train Operations: A Simulation-Based Study." Journal of Vibration Engineering & Technologies 6, no. 3 (June 2018): 197–203. http://dx.doi.org/10.1007/s42417-018-0033-4.

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Cruceanu, Cătălin, and Camil Ion Crăciun. "Effects of Slow-Acting Brakes Application Time Regulated Limits on Freight In-Train Forces." Applied Mechanics and Materials 809-810 (November 2015): 1133–38. http://dx.doi.org/10.4028/www.scientific.net/amm.809-810.1133.

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The paper originally investigates the influence of the admitted ranges of slow-acting filling time of brake cylinder on longitudinal dynamics of freight trains, using experimental air pressure data obtained in tests on filling characteristics. Mechanical and pneumatic models are summarized and numerical simulations were performed for a train composed of six wagon train, in different filling characteristics configurations. The results reflect significant effects on in-train forces values, while evolution and disposition of compression and tensile forces between neighbored vehicles in the long of the train are also affected.

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Wei, Wei, Yang Hu, Qing Wu, Xubao Zhao, Jun Zhang, and Yuan Zhang. "An air brake model for longitudinal train dynamics studies." Vehicle System Dynamics 55, no. 4 (November 25, 2016): 517–33. http://dx.doi.org/10.1080/00423114.2016.1254261.

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Spiryagin, Maksym, Qing Wu, and Colin Cole. "International benchmarking of longitudinal train dynamics simulators: benchmarking questions." Vehicle System Dynamics 55, no. 4 (January 11, 2017): 450–63. http://dx.doi.org/10.1080/00423114.2016.1270457.

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Klauser, P. E. "ADVANCES IN THE SIMULATION OF LONG TRAIN LONGITUDINAL DYNAMICS." Vehicle System Dynamics 17, sup1 (January 1988): 210–14. http://dx.doi.org/10.1080/00423118808969261.

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Shan, Wei, Lai Wei, and Kai Chen. "Longitudinal train dynamics of electric multiple units under rescue." Journal of Modern Transportation 25, no. 4 (September 15, 2017): 250–60. http://dx.doi.org/10.1007/s40534-017-0142-x.

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Wu, Qing, Colin Cole, and Maksym Spiryagin. "Assessing wagon pack sizes in longitudinal train dynamics simulations." Australian Journal of Mechanical Engineering 18, no. 3 (August 27, 2018): 277–87. http://dx.doi.org/10.1080/14484846.2018.1512440.

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Zhu, Tao, Sijing Liu, Shou-ne Xiao, and Quanwei Che. "Train collision dynamic model considering longitudinal and vertical coupling." Advances in Mechanical Engineering 11, no. 1 (January 2019): 168781401882396. http://dx.doi.org/10.1177/1687814018823966.

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The train collision dynamic theory is an acceptable method for new vehicle design, which can save a great deal of simulation and experimentation. A train collision dynamic model that considers the longitudinal and vertical coupling is established. The vehicle subsystem and the track subsystem are also considered in the model through the function of the link between the wheel/rail subsystems and the coupler buffer/anti-climber subsystems. The entire train model is analyzed with a coupled feedback system. The dynamic simulation program of the coupled system is developed, the calculation flow of the coupled model is given, and the explicit time domain solution of the model is realized. Two numerical examples with the same kind of vehicle were completed, and the numerical results are compared with the finite element simulation results. The results show that the coupled model is not only close to the finite element model but also greatly shortens the solution time of the collision response. The accuracy and theory of the collision dynamics model in this article are verified. The results of the paper provide new theoretical evidence and a simulation method for further research on the design of the crashworthiness of rail vehicle structures and the collision dynamic evolution during a train collision.

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Cantone, L. "Simulation of freight trains with up to three traction units in radio communication." IOP Conference Series: Materials Science and Engineering 1214, no. 1 (January 1, 2022): 012039. http://dx.doi.org/10.1088/1757-899x/1214/1/012039.

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Abstract Paper reports the main results of a systematic study on longitudinal train dynamics (LTD) of long freight trains, equipped with radio communication. The simulation results have been used to prepare an experimental test campaign to test the Distributed Power System (DPS) technology. The simulations refer to up/down and level track and they compare the LTD of trains with and without DPS, for different train operations and radio link conditions. The DPS technology is proved (by simulations and test) to be a very effective way to increase the efficiency of future freight trains.

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Jackiewicz, J. "Modeling the longitudinal dynamics of electric multiple units with Xcos/Scilab software." IOP Conference Series: Materials Science and Engineering 1199, no. 1 (November 1, 2021): 012066. http://dx.doi.org/10.1088/1757-899x/1199/1/012066.

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Abstract During the traction and braking of trains, substantial longitudinal dynamic forces might occur in couplers. The method of modeling these forces for two different electric multiple units (EMUs) is presented in this study. For the EMUs consisted of independent vehicles, each of which rests on two bogies, computer simulations were carried out. Simulations were also executed for EMUs with Jacobs bogies, which support bodies of two adjacent carriages. The dynamic modeling of vibration protection train systems includes nonlinearities.

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Uyulan, Caglar, and Ersen Arslan. "Simulation and time-frequency analysis of the longitudinal train dynamics coupled with a nonlinear friction draft gear." Nonlinear Engineering 9, no. 1 (February 7, 2020): 124–44. http://dx.doi.org/10.1515/nleng-2020-0003.

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AbstractTrain safety and operational efficiency can be improved by investigating the dynamics of the train under varying conditions. Longitudinal train dynamics (LTD) simulations performed for such purposes, usually by utilising a nonlinear time-domain model. This paper covers two modes of LTD results corresponding to the time domain and frequency domain analysis. Time-domain solutions are essential to evaluate the full response used for parameter optimisation and controller design studies while frequency domain solutions can provide significant but straightforward clues regarding system dynamics. An advanced draft gear model, which works under a four-stage process is constructed considering all structural components, geometric relationships, friction modelling and dynamic characteristics such as hysteresis, stiffening, state transition, locked unloading, softening. Then, this model is parametrically reduced and implemented into an LTD simulation. The simulation in the time domain is conducted assuming a locomotive connected with a nine wagon via “ode3” fixed-step solver. The transfer function among the first wagon acceleration (output) and the locomotive force (input) estimated through system identification methodology. Then, the identification results interpreted by investigating step-response characteristic and best response giving parameter set is selected. Next, the modal and spectral analysis performed to reveal the behaviour of the in-train forces and the effects of vibration. This paper discusses a reliable methodology for the longitudinal dynamic analysis of the multi-bodied train in time and frequency domain and clarifies in-train vibration behaviour under the existence of sophisticated draft gear.

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SUN, Shulei. "Analysis and Test of Heavy Haul Train Longitudinal Impulse Dynamics." Journal of Mechanical Engineering 53, no. 8 (2017): 138. http://dx.doi.org/10.3901/jme.2017.08.138.

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Wang, Jinghui, and Hesham A. Rakha. "Longitudinal train dynamics model for a rail transit simulation system." Transportation Research Part C: Emerging Technologies 86 (January 2018): 111–23. http://dx.doi.org/10.1016/j.trc.2017.10.011.

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Wu, Qing, Colin Cole, Maksym Spiryagin, and Weihua Ma. "Preload on draft gear in freight trains." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 6 (October 31, 2017): 1615–24. http://dx.doi.org/10.1177/0954409717738849.

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Adjusting draft gear preloads requires minimum or no structural changes to the existing coupler systems. Better or optimal preloads are more promising to be implemented than modifying other parameters such as wedge angles and spring stiffness. This paper presents a method to model draft gear preloads and investigates the numerical step-size requirements for the simulations of draft gear preloads. The implications of preloads on the draft gear impact performance, longitudinal train dynamics performance and coupler fatigue damage were also investigated. The results show that step sizes of less than 2.5 and 0.2 ms (with the fourth Runge–Kutta solver) are recommended to simulate preloads during the simulations of longitudinal train dynamics and wagon impacts, respectively. Wagon impact simulations indicate that the increase of draft gear preloads can noticeably decrease the maximum draft gear deflection during wagon impacts. Longitudinal train dynamics simulations for a distributed power train with 214 vehicles on a 320 km long track were conducted. The longitudinal train dynamics simulations indicate that, when the preload is increased from 0 to 100 kN, the difference of maximum vehicle accelerations is insignificant. When the draft gear preload is further increased to 200 or 300 kN, maximum vehicle accelerations are evidently increased. Draft gear preloads do not noticeably influence the maximum tensile coupler forces. However, preloads have evident implications for maximum compressive coupler forces, especially for the second half of the train. Coupler fatigue damage calculations show that the sum of coupler fatigue damage evidently decreases with the increase of draft gear preload. The damage for the zero preload case is 8.7 times than that of the 300 kN preload case.

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Aboubakr, Ahmed K., Martino Volpi, Ahmed A. Shabana, Federico Cheli, and Stefano Melzi. "Implementation of electronically controlled pneumatic brake formulation in longitudinal train dynamics algorithms." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 230, no. 4 (November 9, 2016): 505–26. http://dx.doi.org/10.1177/1464419316628764.

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The main goal of this investigation is to integrate an electronically controlled pneumatic (ECP) brake model with efficient longitudinal train force algorithms based on the trajectory coordinate formulations. The ECP brake model, developed in this investigation consists of the train line (cable), locomotive automatic brake valve, air brake pipe, and ECP manifold. The train line, which covers the entire length of the train, allows the brake commands to be received by the car simultaneously. While pneumatic pressure is used to generate the braking forces, the brake pipe is no longer used to provide the brake level commands. Instead, the brake pipes are used to provide a continuous supply of compressed air stored in a reservoir mounted on each railcar. Using the ECP system to apply the brakes uniformly and instantaneously gives better train control, shortens the stopping distances, and leads to a lower risk of derailment. In this investigation, the fluid continuity and momentum equations are used to develop the governing air pressure flow equations. These partial differential equations are converted to a set of ordinary differential equations using the finite element method leading to an air brake force model that accounts for the effect of the air flow in long train pipes as well as the effect of leakage and branch pipe flows. The car brake forces are applied to the wheels using the ECP manifold located in each car. The ECP manifold used in this investigation has four valves: cut-off valve, vent valve, auxiliary valve, and emergency valve. The ECP manifold is connected to three main pneumatic components: the auxiliary reservoir, the emergency reservoir, and the brake cylinder. The reservoirs serve as the main storage of the pressurized air, while the brake cylinder and other mechanical components such as the rigging and the brake shoes transmit the brake force to the wheels. In this investigation, a mathematical model of the ECP manifold and its components is developed. The relationship between the main components of the ECP brake system and the train dynamics is discussed, and the final set of differential equations that integrates the ECP brake and train dynamics is presented. Different simulation scenarios are considered in this study in order to investigate the effect of the brake forces on the train longitudinal dynamics in the case of different braking scenarios. The performance of the developed ECP brake system is compared with the Association of American Railroads safety and operation standards, and with experimental results published in the literature.

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Polyakov, Vladislav A., and Nikolai M. Khachapuridze. "Magnetically levitated train’s longitudinal motion (Simulation results)." Transportation Systems and Technology 4, no. 3 (November 2, 2018): 143–53. http://dx.doi.org/10.17816/transsyst201843143-153.

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Background: The no-stationary regimes of the magnetically levitated train’s (MLT) motion were the object of research. Aim: The purpose of the study is to evaluate its dynamic qualities and loading in such regimes. Methods: The work was carried out by conducting a series of experiments with a computer model of train’s dynamics. Results: The simulation results reflect its motion in the modes of acceleration, passage of the tunnel, as well as service and emergency braking. Conclusion: An analysis of these results made it possible to evaluate the dynamic properties of a train in various non-stationary motion modes and its loading in their process.

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Celiński, Ireneusz, Rafał Burdzik, Jakub Młyńczak, and Maciej Kłaczyński. "Research on the Applicability of Vibration Signals for Real-Time Train and Track Condition Monitoring." Sensors 22, no. 6 (March 18, 2022): 2368. http://dx.doi.org/10.3390/s22062368.

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The purpose of this research was to analyze the possibilities for the application of vibration signals in real-time train and track control. Proper experiments must be performed for the validation of the methods. Research on vibration in the context of transport must entail many of the different nonlinear dynamic forces that may occur while driving. Therefore, the paper addresses two research cases. The developed application contains the identification of movement and dynamics and the evaluation of the technical state of the rail track. The statistics and resultant vector methods are presented. The paper presents other useful metrics to describe the dynamical properties of the driving train. The angle of the resultant horizontal and vertical accelerations is defined for the evaluation of the current position of cabin. It is calculated as an inverse tangent function of current longitudinal and transverse, longitudinal and vertical, transverse, and vertical accelerations. Additionally, the resultant vectors of accelerations are calculated.

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Zhang, Jingke, Xiaorui Wang, Tao Zhu, Bing Yang, Shoune Xiao, Guangwu Yang, Yanwen Liu, and Benhuai Li. "Research on Calculation Method for Maximum Mean Acceleration in Longitudinal Train Collision." Shock and Vibration 2021 (September 17, 2021): 1–16. http://dx.doi.org/10.1155/2021/1560297.

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A large number of numerical simulations are required to design an energy absorption scheme for train crashworthiness, leading to low design efficiency in the early stage. Based on train collision dynamics theory and the finite element method, a dynamic finite element model of longitudinal train collision is established. According to the model, we studied the acceleration time-history characteristics during the train collision process, obtained the mean-peak ratio coefficient, and determined the calculation formula for the maximum mean acceleration of a longitudinal train collision. Through characteristic analysis of the vehicle acceleration, interface force, and other parameters during a longitudinal train collision, the calculation method of the mean acceleration was improved. The analysis shows that the maximum mean acceleration depends on two stages in the collision process: (1) the coupler action of the head vehicle: the mean-peak ratio coefficient of the head vehicle is 0.7 in this stage, and the mean-peak ratio coefficient of other vehicles is 0.43; (2) the coupler of the collision interface is cut off, and the energy absorption devices of the head vehicle or intermediate vehicle absorb energy; the mean-peak ratio coefficient of the vehicle is 0.93 in this stage. On this basis, a mathematical function is established describing the mean acceleration of the vehicle and the average crushing force of the coupler collapse tube and the energy-absorbing device. The calculation formula is obtained for the maximum mean acceleration of the longitudinal train collision, and the results are compared with the mean acceleration obtained by numerical simulation. The Kruskal–Wallis ANOVA multisample independent nonparametric test was conducted to verify the reliability of the calculation results in the 95% confidence interval. The calculation formula can be used to calculate the maximum mean acceleration in the energy allocation stage of train crashworthiness design to effectively improve the efficiency of train collision energy allocation.

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Jha, Prabin Kumar, and Sadanand Sadashiv Gokhale. "Validation of longitudinal dynamics of Gatimaan Express model in Matlab/Simulink®." Mechanics & Industry 19, no. 3 (2018): 307. http://dx.doi.org/10.1051/meca/2018030.

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This paper presents a mathematical model of longitudinal dynamics of Gatimaan Express. It has one locomotive class WAP5, two generator vans, eight second class chair cars and two executive chair cars respectively. Forces associated with longitudinal dynamics of model are developed in Matlab/Simulink. Longitudinal and coupler forces as well longitudinal velocities are studied during the failure of coupler of 3rd (coach of middle train) second class chair. Validation of longitudinal velocity of the model is done by comparing simulated results with measured field data provided by Research Designs Standards Organization (RDSO), Lucknow, India.

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Wu, Qing, Colin Cole, Maksym Spiryagin, and Tim McSweeney. "Parallel multiobjective optimisations of draft gear designs." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 3 (January 31, 2017): 744–58. http://dx.doi.org/10.1177/0954409717690981.

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This paper presents the methodology and results of the parallel multiobjective optimisations of draft gear designs. The methodology used white-box draft gear models, whose parameters were used as the optimisation variables. Two optimisation algorithms were used: genetic algorithm and particle swarm optimisation. All the optimised draft gear designs were constrained by impact tests to ensure that the optimised designs also comply with the current acceptance standards for draft gears. The performance of draft gears was assessed using whole-trip longitudinal train dynamics simulations and coupler fatigue damage calculations. Each simulation covered a round trip (loaded one way, empty on return) over a total of 640 km of track, which involved about 10 h of operational time. Three optimisation objectives were considered: minimal fatigue damage for wagon connection systems of loaded trains, minimal in-train forces for loaded trains, and minimal longitudinal wagon accelerations for empty trains. Two case studies were presented, which optimised two types of draft gears (single-stage and double-stage draft gears) using genetic algorithm and particle swarm optimisation, respectively.

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HAMAJIMA, Toyokazu, Kazuhiko NISHIMURA, and Yoshiaki TERUMICHI. "1D23 A study of train set motion with large displacement and deformation under longitudinal excess force condition(Vehicles-Dynamics)." Proceedings of International Symposium on Seed-up and Service Technology for Railway and Maglev Systems : STECH 2015 (2015): _1D23–1_—_1D23–12_. http://dx.doi.org/10.1299/jsmestech.2015._1d23-1_.

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Li, Yi Ping. "Study on Impact Properties of New Hydro-Pneumatic Buffer for a Metro Vehicle." Advanced Materials Research 978 (June 2014): 94–100. http://dx.doi.org/10.4028/www.scientific.net/amr.978.94.

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Analyzed and studied the hydro-pneumatic buffer structure of railway vehicle, designed a new type of hydro-pneumatic buffer and established the detailed dynamics model. Calculated the static characteristic curve of hydro-pneumatic buffer with different compression rate and dynamic characteristic curve with different impact speed through the numerical simulation method. The simulation results shows that the biggest impedance force is 1836.3KN and buffer capacity reach 221.89KJ when impact velocity of the new hydro-pneumatic buffer is 5m/s.New hydro-pneumatic buffer can improve the speed of manipulating vehicle, reduce the longitudinal impact and vibration in the train and adapt to the needs of the trains.

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Pan, Bo, Wei Zhang, Jianqiu Cao, Xueyong Ma, and Mingliang Zhou. "Dynamic Responses of Soils around a One-Hole Double-Track Tunnel with the Metro Train Meeting." Shock and Vibration 2020 (January 13, 2020): 1–16. http://dx.doi.org/10.1155/2020/1782803.

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The single-hole double-track shield tunnel with a large diameter has been one of the optimized schemes for those Metro meeting tunnels crossing long water areas. Compared with single-hole single-track tunnels, train-meeting scenarios occur in single-hole double-track tunnels, which results in a greater dynamic loading and a longer action time. By far, the thorough understanding of the dynamic response and liquefiability of the soils around the single-hole double-track tunnels, when crossing liquefiable soil layers, is still lacked. In this paper, a typical profile of Nanjing Metro Line 10, of the crossing-river section near Jiangxinzhou Station, is taken as an example. Based on the multibody dynamics, we established the train-rail coupling model to obtain the train dynamic load. Subsequently, in view of the single running scenario and four typical meeting scenarios, the train-tunnel-soil FEM model is developed to analyse the dynamical responses of the soils around the tunnel. The results indicate the vertical acceleration of the tunnel substrata exhibits an exponential attenuation trend with an increase of the distance; the horizontal acceleration of the ground surface exhibits an enlarged area within 10–25 m from the tunnel centerline. Also, the displacement of the soil layer under the tunnel increases cyclically in the period of the Metro train passing and rebounds slowly after the train passes. When the wheels of two Metro trains act simultaneously, the peak compression strain increases superimposedly; when the act is out of sync, the peak compression strain occurs concentrated and significant increase does not occur. Moreover, the larger the vibration amplitude the Metro train causes, the greater the excess pore water pressure occurs. Beyond a certain depth range, the influence of the vibration vanishes. The ratio of the maximal pore water pressure to the total stress is less than 1, suggesting that liquefaction does not occur in the silty-fine sand soil layer beneath the tunnel. The research results can be used to estimate the longitudinal differential settlement under long-term operation conditions and be helpful in regulating running speed of the Metro trains and planning the maintenance measures for the track flatness of the tunnel.

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Qi, Yayun, and Huanyun Dai. "Influence of motor harmonic torque on wheel wear in high-speed trains." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 1 (February 21, 2019): 32–42. http://dx.doi.org/10.1177/0954409719830808.

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With the increase of train speed, the harmonic torque of the traction motor of a high-speed train is not a negligible source of excitation. In order to explore the influence of the harmonic torque of the motor on wheel wear, a high-speed EMU vehicle model was established based on the multibody dynamics theory. FASTSIM was used to calculate the wear parameters, and the Zobory wear model was used to calculate the depth of the wheel wear. The influence of the harmonic torque of the motor on the wear parameters and wear depth of high-speed trains under straight and curve conditions is calculated, respectively. The simulation results show that the harmonic torque has a large influence on the wheel rail vertical force and the longitudinal creep force and has little influence on the lateral creep force. With the 30% harmonic torque, the wheel rail vertical force increases by 7.6%, the longitudinal creep force increases by 15%, and the lateral creep force increases by 4%. The amplitude of the longitudinal creepage increases by 14.2% when the harmonic torque is 10%, and increases by 34.4% when the harmonic torque is 30%. When the harmonic torque increases, the wheel wear depth increases, the 10% harmonic torque increases by 3% and the 30% harmonic torque increases by 8%, and the increase of the motor harmonic component accelerates the wheel wear. At the same time, small longitudinal positioning stiffness can help to reduce the influence of the harmonic torque, and the selection of the longitudinal positioning stiffness needs to consider the dynamic performance of the vehicle.

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Кеглин, Борис, Boris Keglin, Алексей Васильев, Aleksey Vasilev, Алексей Болдырев, Aleksey Boldyrev, Александр Гуров, and Aleksandr Gurov. "Research of freight car´s longitudinal loading equipped new frictional absorbing devices." Bulletin of Bryansk state technical university 2014, no. 1 (March 31, 2014): 12–17. http://dx.doi.org/10.12737/23366.

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The distribution of longitudinal forces acting on the freight car with new frictional absorbing devices was built. The impact of various absorbing devices on the train longitudinal dynamics was investigated. The statistical spectrum of forces at various modes of exploitation of the car was defined

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Wu, Meng Ling, Teng Peng Chen, Yue Chao Lu, and Meng Ting Cheng. "Modeling and Simulation of Deceleration-Oriented Braking Control on Freight Train." Applied Mechanics and Materials 88-89 (August 2011): 77–81. http://dx.doi.org/10.4028/www.scientific.net/amm.88-89.77.

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Based on the original Electronically Controlled Pneumatic (ECP) brake system of the heavy-haul freight train and SIMULINK, in this paper we establishes the vehicle longitudinal dynamics model and a new braking control mode (deceleration control) in order to reduce the shock caused by the impulse of the vehicles to the coupler so as to lessen the danger of coupler fracture. The author adopts the Smith-PID control compensating method as the core of the deceleration control so as to control the vehicle longitudinal dynamics model. Furthermore, by calculating the variation of the coupler force and comparing with the results of the original braking force control method, theoretically we can draw conclusion that deceleration control has high feasibility and superiority.

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Lei, Cheng, Jia Liu, Lisheng Dong, and Weihua Ma. "Influence of Draft Gear Modeling on Dynamics Simulation for Heavy-Haul Train." Shock and Vibration 2019 (July 28, 2019): 1–11. http://dx.doi.org/10.1155/2019/2547318.

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In order to study the impedance characteristics of the frictional draft gear, MT-2 draft gear is studied, and its mechanical properties are analyzed firstly. Then, the mathematical models of two common draft gears are established based on the data collected from the vehicle impact test, and the effects of the two modeling methods on the simulation results are compared through the shunting impact test and the bench test simulation. Researches show that, under various experimental conditions, the simulated draft gear characteristic curve of the lookup table model moves along a fixed trajectory regardless of the change rate of the draft gear stroke, while simulation results of the wedge-spring model depend on the change rate of the draft gear stroke and are more consistent with the experimental results, reflecting the dynamic characteristics of the draft gear and suggesting better adaptability and wider application. Finally, the “1 + 1” grouped 20,000-ton heavy-haul combined train model is established, with its draft gear characteristics under the full-braking condition on flat straight track analyzed. Calculation results and test results of the lookup table model and the wedge-spring model are compared, indicating that using the wedge-spring model to calculate the longitudinal dynamics performance is more accurate. The influence of the modeling on the longitudinal impulse simulation of the train after air braking is also studied, revealing that the variation trends of the coupler force curves of two models are basically the same, but the amplitude and frequency of the longitudinal impulse are different.

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Sharma, Sunil Kumar. "Multibody analysis of longitudinal train dynamics on the passenger ride performance due to brake application." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 233, no. 2 (July 31, 2018): 266–79. http://dx.doi.org/10.1177/1464419318788775.

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In this paper, longitudinal train dynamics and coupler forces were modelled based on experimental results of Research Design and Standard Organisation and from the available literature. The model was solved numerically in MATLAB. Moreover, a multibody model was developed in Universal Mechanism software considering a locomotive and two coaches that were validated with the mathematical model by comparing acceleration responses of locomotives and coaches running at 150 km/h and then applying emergency braking. The validated model in the Universal Mechanism software was extended and used for additional study. For the case study, the Rajdhani Express train was considered running at its maximum operational speed of 160 km/h with track gradient of New Delhi and Agra Cantt station. The performance of the rail vehicle in five braking phases was evaluated. The maximum compression force in coupler increased after the application of each brake phase. Moreover, the maximum compressive coupler force of 149 t was experienced at the third quarter of the train. However, the ride quality and comfort were within the satisfactory range prescribed by Research Design and Standard Organisation.

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Kovalev, R., A. Sakalo, V. Yazykov, A. Shamdani, R. Bowey, and C. Wakeling. "Simulation of longitudinal dynamics of a freight train operating through a car dumper." Vehicle System Dynamics 54, no. 6 (March 16, 2016): 707–22. http://dx.doi.org/10.1080/00423114.2016.1153115.

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Pogorelov, Dmitry, Vladislav Yazykov, Nikolay Lysikov, Ercan Oztemel, Omer Faruk Arar, and Ferhat Sukru Rende. "Train 3D: the technique for inclusion of three-dimensional models in longitudinal train dynamics and its application in derailment studies and train simulators." Vehicle System Dynamics 55, no. 4 (January 11, 2017): 583–600. http://dx.doi.org/10.1080/00423114.2016.1273532.

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Naeimi, Meysam, Meisam Tatari, and Amin Esmaeilzadeh. "Dynamics of the Monorail Train Subjected to the Braking on a Straight Guideway Bridge." Archive of Mechanical Engineering 62, no. 3 (September 1, 2015): 363–76. http://dx.doi.org/10.1515/meceng-2015-0021.

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Abstract A finite element (FE) model of the straight guideway bridge under monorail train has been built in this research in order to investigate dynamic interactions of the coupled system in the vertical and longitudinal direction. A limited length of the straddle monorail bridge including five continuous spans is modeled in three dimensions by using FE method. A 3D model of the monorail train system, built in the multibody analyzer MSC ADAMS, is assembled over the bridge. The entire model, consisting of the vehicle and bridge subsystems, is numerically analyzed by performing dynamic simulation in time domain. The braking forces between the train tires and guideway beams are activated in the analysis, in addition to the dead weights of the components and the train live loads. Dynamic forces in the tires are obtained for the case of the emergency braking in the system. The reaction forces, appeared in the bridge piers, are reported as the input forces for the purpose of the bridge design.

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Sidorova, E. A., V. O. Pevzner, and A. I. Chechel’nitskiy. "Indicators of the force interaction of the track and rolling stock when a freight car runs on long irregularities, taking into account the action of longitudinal forces." VNIIZHT Scientific Journal 80, no. 6 (December 27, 2021): 359–65. http://dx.doi.org/10.21780/2223-9731-2021-80-6-359-365.

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Authors describe formation mechanism of long irregularities of the railway track and the importance of their elimination for the track facilities. Based on the results of freight train operation modeling on long irregularities in the traction mode, an analysis of the processes occurring during the motion of heavy trains along a track with such deviations was carried out, modeling was carried out on the basis of the “Universal Mechanism” software package. Based on the results of the calculation, interaction between the track and the rolling stock in the vertical plane was assessed in terms of the magnitude of the vertical force and coeffcients: dynamics, stability margin, Nadal, unloading (in percent) of axle springs of freight car springs. Article analizes the nature of the infuence of the irregularity slope on the decrease in the vertical force transmitted from the wheel to the rail and the change in the traction force on the dynamics of freight cars in the train and passing on long irregularities of the longitudinal profle through the indicators of the vertical force.

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Zhang, Rang, and Gang Shen. "Cooperative Control of Tire Longitudinal and Lateral Forces of Distributed Drive Virtual Rail Train." Journal of Physics: Conference Series 2437, no. 1 (January 1, 2023): 012117. http://dx.doi.org/10.1088/1742-6596/2437/1/012117.

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Abstract Hub motors are distributed on different wheels of the virtual rail train (VRT), forming a distributed drive mode, which is conducive to simplifying the transmission system and improving the stability and mobility of VRT. How to coordinate the relationship between the longitudinal and lateral forces of tires is a problem that must be solved. This paper proposes a hierarchical cooperative control method of the longitudinal and lateral forces of tires, in which the control decision-making layer ensures the steering stability and path following performance of VRT, and establishes an objective function based on the tire load rate at the distribution layer to distribute the longitudinal and lateral forces of each tire. The co-simulation results based on MATLAB / Simulink and multi-body dynamics software UM show that the cooperative control method not only ensures the specific track requirements of the train, but also reduces the peak load rate of the tire, optimizes the distribution of the load rate, and greatly improves the stability of the train in the steering process.

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Xin, Tao, Pengsong Wang, and Yu Ding. "Effect of Long-Wavelength Track Irregularities on Vehicle Dynamic Responses." Shock and Vibration 2019 (March 12, 2019): 1–11. http://dx.doi.org/10.1155/2019/4178065.

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Long-wavelength track irregularities have obvious influence on ride comfort and running stability of high-speed trains. Meanwhile, it brings risk to the inspection of track irregularities since ordinary inspection equipment has difficulties in covering long wavelengths. Previous research on the effect of long-wavelength track irregularities is rare. In order to find the relationship between long-wavelength irregularities and vehicle dynamic responses, a numerical vehicle-track coupling dynamic model based on multibody dynamics and finite element theories is established by using a self-compiling program. One case study is given as an example to show the methodology of determining the sensitive long wavelength and management amplitude of track longitudinal-level irregularities in high-speed railway. The simulation results show that the sensitive long wavelength has a strong correlation with train speed and natural frequency. The simulation and field test results are in good agreement.

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Wang, Haitao, and Huanhuan Gao. "Study of Blockage Effects of Metro Train on Critical Velocity in Sloping Subway Tunnel Fires with Longitudinal Ventilation." Energies 15, no. 15 (August 8, 2022): 5762. http://dx.doi.org/10.3390/en15155762.

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Critical velocity is very important for smoke control in longitudinally ventilated subway tunnel fires. Numerical investigations are conducted in this paper to study the impacts of metro train blockages on critical velocity in sloping subway tunnel fires by using fire dynamics simulator (FDS) tunnel models validated with the field-experiment data. Moreover, a global model of critical velocity is presented for the blocked zone of a metro train in subway tunnel fires including influencing factors of the blockage ratio and tunnel slope. The results show that the reduction ratio of critical velocity in the blocked zone is less than the metro-train blockage ratio. The correction factor between the critical velocity reduction ratio and metro-train blockage ratio is 0.545. The aerodynamic shadow zone downstream of a subway train blockage has important impacts on the critical velocity. The critical velocity in the unblocked zone of a metro train is higher than that in the blocked zone of a metro train blockage. The reason is that smoke flow is hindered by the metro train blockage in subway tunnel fires. With an increase in the blockage–fire source distance, the critical velocity first decreases and then tends to be constant. The global model presented can accurately predict the critical velocity in a sloping subway tunnel with a train blockage. The results may provide beneficial suggestions for designing ventilation systems for subway tunnels.

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Journal articles on the topic 'Longitudinal train dynamics'

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