Simulation of longitudinal dynamics of a freight train operating through a car dumper

Kovalev, Roman; Sakalo, A.; Yazykov, Vladislav; Shamdani, Amir Hossein; Bowey, R; C, Wakeling

doi:10.1080/00423114.2016.1153115

Cited by 31 publications

(14 citation statements)

References 10 publications

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“…Modelling of LTD has been discussed in many publications 21–30 ; specifics are not discussed in this paper. All simulations in this paper are carried out using the Train Dynamics and Energy Analyser/Train Simulator 1 that was initially developed in the State Key Laboratory of Traction Power (TPL), China and further jointly developed by TPL and Centre for Railway Engineering, Australia.…”

Section: Implications Of Preload For Ltdmentioning

confidence: 99%

Preload on draft gear in freight trains

Cole

Spiryagin

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part F:

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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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Section: Implications Of Preload For Ltdmentioning

confidence: 99%

Preload on draft gear in freight trains

Cole

Spiryagin

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part F:

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show abstract

“…In fact, these elements have strongly non-linear force-deflection characteristics and feature a hysteretic loop, as highlighted by experimental drop-hammer tests. 1,7,8 Nowadays, long trains are modeled as single degree of freedom (d.o.f.) lumped mass systems, made up of several point masses, representing the wagons, connected to each other through non-linear elements, which include the characteristic of the entire coupling system, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, these elements have strongly non-linear force–deflection characteristics and feature a hysteretic loop, as highlighted by experimental drop-hammer tests. 1,7,8…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a new code for longitudinal train dynamics simulation

Bosso

Magelli

Zampieri

2020

Proceedings of the Institution of Mechanical Engineers, Part F:

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Longitudinal train dynamics have a significant impact on both safety and performance of railway systems. Numerical simulation of long heavy haul trains can thus provide essential information for the development of diagnostic and signaling systems as well as coupling elements and braking systems. Long trains are usually modeled by considering only the longitudinal degree of freedom and by adding extra resistant forces to represent the track curvature and gradients. The prediction of in-train forces represents the most critical aspect in modeling the longitudinal dynamics of long trains made up of several vehicles. In fact, coupling elements have non-linear force–deflection characteristics, with different behavior in loading and unloading states, thus featuring a hysteretic loop. Look-up tables storing data from experimental tests are generally used to model these elements; however, other strategies, such as fitting curves and white-box models are witnessed in the literature. Recently, an international benchmarking of longitudinal train dynamics simulator was established in order to compare the output results obtained by different models with the same input data. The research group from Politecnico di Torino performed the simulations using the multibody software Simpack, but computational inefficiencies and numerical divergences occurred. To overcome these issues, a new dedicated in-house code was developed in the MATLAB environment. The paper focuses on the description of this new code and its validation, which was carried out by performing the simulations according to the benchmark inputs and comparing the results with the outputs from the other participants.

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“…The model calculates the braking pressure time histories along the train and the forces exchanged in the longitudinal direction and was validated for use by the UIC. Similar software packages have been developed elsewhere such as CRE-LTS, 2 UM, 4 TSDYN, 5 and ATTIF. 6 Many of the simulation packages usually provide time histories of longitudinal in-train forces that develop along a long freight train, subjected to various vehicle attributes, gradients and operating scenarios such as braking, traction, etc.…”

Section: Introductionmentioning

confidence: 99%

An integrated numerical framework to investigate the running safety of overlong freight trains

Krishna

Jobstfinke

Melzi

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part F:

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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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Simulation of longitudinal dynamics of a freight train operating through a car dumper

Cited by 31 publications

References 10 publications

Preload on draft gear in freight trains

Preload on draft gear in freight trains

Development and validation of a new code for longitudinal train dynamics simulation

An integrated numerical framework to investigate the running safety of overlong freight trains

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