scholarly journals Effect of vertical imperfections on longitudinal railway track response

2019 ◽  
Vol 262 ◽  
pp. 11003
Author(s):  
Wlodzimierz Czyczula ◽  
Lukasz Chudyba
Keyword(s):  
Critical Speed ◽  
Linear Models ◽  
Railway Track ◽  
Traction Forces ◽  
Stationary Response ◽  
Rail Track ◽  
Train Speed ◽  
Short Time

The paper presents an analysis of linear models track response under longitudinal loads due to braking and accelerating of the train as well as constant traction forces. Longitudinal forces on the wheel-rail contacts are uniformly distributed on the whole length of train. Analysis is carried out under assumption that – in short time – train speed does not change significantly. Therefore stationary response of rail track is considered. The problem of critical speed is presented. Effect of vertical imperfections on the longitudinal rail displacement is considered under assumption that longitudinal forces varying in time are changed proportionally to the vertical forces. These forces are proportional to the amplitude of vertical imperfections. This analysis should be recognised as the main novelty of the paper. In the summary, certain practical conclusions are formulated as well as the further investigations are pointed out.

scholarly journals Dynamic response of rail track in longitudinal direction

2018 ◽  
Vol 2018 (7) ◽  
pp. 1-9 ◽  
Author(s):  
Włodzimierz Czyczuła ◽  
Łukasz Chudyba
Keyword(s):  
Dynamic Response ◽  
Critical Speed ◽  
Linear Models ◽  
Longitudinal Direction ◽  
Damping Properties ◽  
Stationary Response ◽  
Rail Track ◽  
Train Speed ◽  
Short Time

The paper presents an analysis of linear models track response under longitudinal loads due to braking/accelerating of the train. Longitudinal forces are uniformly distributed on the whole length of the train. Analysis was carried out under assumption that – in the short time – train speed not changes significantly. Therefore stationary response of rail track is considered. The problem of critical speed has been analyzed. Effect of damping properties of track foundation on maximum longitudinal displacements were also considered. In summary certain practical conclusions were formulated as well as the further investigations were pointed out.

scholarly journals Investigation into Impact of Train Speed for Behavior of Ballasted Railway Track Foundations

2016 ◽  
Vol 143 ◽  
pp. 1152-1159 ◽  
Author(s):  
Md. Abu Sayeed ◽  
Mohamed A. Shahin
Keyword(s):  
Railway Track ◽  
Train Speed

Rail Track Surface Image Acquisition and Positioning

2013 ◽  
Vol 278-280 ◽  
pp. 1143-1147
Author(s):  
Liang Sun ◽  
Jun Zhang ◽  
Zhe Chen ◽  
Long Guo ◽  
Jia Ge ◽  
...  
Keyword(s):  
High Speed ◽  
Detection System ◽  
Output Pulse ◽  
Location Information ◽  
Optical Encoder ◽  
Rail Track ◽  
Surface Image ◽  
Train Speed ◽  
Track Surface ◽  
Time Acquisition

Rail track surface detection system was constructed to detect the rail track surface. The mismatch between the train speed, rail track location and camera trigger speed was solved during the real-time acquisition process about the rail track using optical encoder and GPS module. In our system, optical encoder was used to reflect the train speed and output pulse to externally trigger the line scan high-speed camera exposure. At the same time, another pulse of optical encoder was transmitted to the computer to save the GPS location information. So the rail track images are saved with the track location information.

Out-of-Plane Responses of Overspeeding High-Speed Train on Curved Track

2018 ◽  
Vol 18 (11) ◽  
pp. 1850132 ◽  
Author(s):  
Jian Dai ◽  
Kok Keng Ang ◽  
Van Hai Luong ◽  
Minh Thi Tran ◽  
Dongqi Jiang
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Contact Forces ◽  
Railway Track ◽  
High Speed Train ◽  
Track Segment ◽  
Out Of Plane ◽  
Train Speed ◽  
Curved Track ◽  
Design Speed

This paper presents a numerical study on the out-of-plane responses of a high-speed train running on a curved railway track segment using the moving element method. The accuracy and efficiency of the proposed computation model presented herein are compared with available analytical results from the literature and a finite element solver based on a simplified moving load model. Thereafter, a half-railcar moving sprung-mass model and a double-rail track-foundation model are presented to investigate the behavior of a high-speed train traversing a curved track, particularly when the train speed is greater than the design speed of the curved track segment. The results show that the train speed and severity of track irregularity significantly affect the contact forces on the rails. This paper also presents a case of a railcar overturning when the train speed is greater than 2.5 times the design speed of a curved track segment.

scholarly journals Rethinking rail track switches for fault tolerance and enhanced performance

2016 ◽  
Vol 231 (9) ◽  
pp. 1048-1065 ◽  
Author(s):  
Samuel D Bemment ◽  
Emma Ebinger ◽  
Roger M Goodall ◽  
Christopher P Ward ◽  
Roger Dixon
Keyword(s):  
Fault Tolerance ◽  
Railway Track ◽  
The Novel ◽  
Functional Requirements ◽  
Rail Track ◽  
Rail Network ◽  
Solution Generation ◽  
Switch Design ◽  
Novel Concept ◽  
Novel Design

Railway track switches, commonly referred to as ‘turnouts’ or ‘points,’ are a necessary element of any rail network. However, they often prove to be performance-limiting elements of networks. A novel concept for rail track switching has been developed as part of a UK research project with substantial industrial input. The concept is currently at the demonstrator phase, with a scale (384 mm) gauge unit operational in a laboratory. Details of the novel arrangement and concept are provided herein. This concept is considered as an advance on the state of the art. This paper also presents the work that took place to develop the concept. Novel contributions include the establishment of a formal set of functional requirements for railway track switching solutions, and a demonstration that the current solutions do not fully meet these requirements. The novel design meets the set of functional requirements for track switching solutions, in addition to offering several features that the current designs are unable to offer, in particular to enable multi-channel actuation and rail locking, and provide a degree of fault tolerance. This paper describes the design and operation of this switching concept, from requirements capture and solution generation through to the construction of the laboratory demonstrator. The novel concept is contrasted with the design and operation of the ‘traditional’ switch design. Conclusions to the work show that the novel concept meets all the functional requirements whilst exceeding the capabilities of the existing designs in most non-functional requirement areas.

scholarly journals Investigation of KPP-5 Rail Fastener Elastic Deformation

2018 ◽  
Vol 15 (4) ◽  
pp. 5815-5825
Author(s):  
R. V. Markul ◽  
N. P. Nastechik ◽  
V. V. Kovalchuk ◽  
Y. M. Hnativ
Keyword(s):  
Elastic Deformation ◽  
Railway Track ◽  
Pressing Force ◽  
Rail Track ◽  
Long Period ◽  
Rail Wear ◽  
Main Influence

For a long period of operation, a number of shortcomings have been identified in KPP-5 fastener that is mainly due to an intensive decrease of pressing force of the rail on sleepers. This leads to the appearance of frequent cases of track displacement and fastening elements failure. To verify such hypothesis, the process of power work of KPP-5 fastener during railway track operation was researched. The technique and practical means of controlling the power work of KPP-5 fastener are developed. The influence of various factors of the rail pressing force on the sleeper is determined. The main influence is conditioned by under-rail wear (50.4%). The obtained results made it possible to formulate recommendations for the improvement of KPP-5 fastener where the methodology and practical means of controlling the power work of KPP-5 fastener were proposed. At the same time, it allows increasing the reliability and safety of the rail track during the entire overhaul period.

scholarly journals Mathematical modeling and analysis of dynamic phenomena turnout rail

2017 ◽  
Vol 2017 (10) ◽  
pp. 36-44
Author(s):  
Rafał Kowalik ◽  
Emil Sadowski
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Models ◽  
Railway Track ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Modeling And Analysis ◽  
Rail Track ◽  
Pass Through ◽  
Dynamic Phenomena

The article presents the results of simulations carried out for the developments on the railway junction in the instantaneous passage of a railway vehicle. The main focus lies on getting runs all three forces present in the area of the point of contact wheel-rail. Tests carried out for different vehicle speed rail-track. In addition, also presented mathematical models describing the motion of the train to pass through the railway track and discusses the mathematical considerations describing the deflection of the beam under the influence of rolling wheels on it. At the end shows the conclusions of the simulations.

scholarly journals Determination of the maximum dangerous width of a rail track on a reinforced concrete base with fasteners of the КБ type, taking into account all influencing factors

2021 ◽  
pp. 113-120
Author(s):  
Vadym Novikov ◽  
Andriy Babenko ◽  
Oleksandr Kharkivskyi ◽  
Olena Olexandrivna Tkachenko
Keyword(s):  
Reinforced Concrete ◽  
High Speed ◽  
Railway Track ◽  
Rolling Stock ◽  
Lateral Direction ◽  
Maximum Width ◽  
Rail Track ◽  
Emergency Braking ◽  
Simultaneous Influence

Railway track retention standards in Ukraine do not take into account theconstruction of the subrail base, but regulate one for all types maximum dangerous value of the trackwidth, which was changed from 1546 mm to 1548 mm without any justification of scientific researchor explanations of the effects of tolerances the width of the rail track and the wheel track, which ingeneral at that time were not fully investigated but taking into account the emergence anddevelopment of new scientific problems associated with the emergence of intensive lateral wear ofrails and ridges of locomotive and wagon wheels. The deterministic dependences of lateralimpressions of the P65 type rail thread head on the simultaneous influence of vertical and horizontalforces for the newly installed repair profiles of UZ rolling stock on the basis of previously performedexperimental and theoretical studies were investigated. The results allow at this stage of research todetermine and calculate the practical values of the maximum dangerous width of the track, in whichthe subrail base consists of reinforced concrete sleepers and separate rail fasteners, which are usedboth on conventional highways with mixed traffic and on high-speed lines UZ.The article establishes the need to take into account new factors influencing the dangerouswidth of the rail track with intermediate rail fasteners of separate type depending on the load stress of sections and new repair profiles of rolling stock, as well as wear processes of intermediate railfasteners type KБ and its elements on the appearance of elastic backlash in the lateral direction fromthe influence of the guide wheels of the rolling stock. The recommended value of the maximum widthof the rail track for areas where service or emergency braking is applied - 1550 mm, taking intoaccount that the contact of the wheel and the rail is not at a point, but on an ellipse. The establishednorm of the maximum width of a rail track allows to define economic efficiency of introduction in theconditions of operation of a track in curved sections of a track of small radii with limited use of themaximum admissible lateral wear (15 mm) of a head of a rail thread provided that the normal-forcedentry of rolling stock carts.

scholarly journals Measuring change in biological communities: multivariate analysis approaches for temporal datasets with low sample size

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11096
Author(s):  
Hannah L. Buckley ◽  
Nicola J. Day ◽  
Bradley S. Case ◽  
Gavin Lear
Keyword(s):  
Time Series ◽  
Sample Size ◽  
Statistical Power ◽  
Structural Changes ◽  
Linear Models ◽  
Environmental Changes ◽  
Short Time Series ◽  
Biological Communities ◽  
Extinction Events ◽  
Short Time

Effective and robust ways to describe, quantify, analyse, and test for change in the structure of biological communities over time are essential if ecological research is to contribute substantively towards understanding and managing responses to ongoing environmental changes. Structural changes reflect population dynamics, changes in biomass and relative abundances of taxa, and colonisation and extinction events observed in samples collected through time. Most previous studies of temporal changes in the multivariate datasets that characterise biological communities are based on short time series that are not amenable to data-hungry methods such as multivariate generalised linear models. Here, we present a roadmap for the analysis of temporal change in short-time-series, multivariate, ecological datasets. We discuss appropriate methods and important considerations for using them such as sample size, assumptions, and statistical power. We illustrate these methods with four case-studies analysed using the R data analysis environment.

scholarly journals Research of safety indicators of diesel train movement with two-stage spring suspension

2018 ◽  
Vol 234 ◽  
pp. 05003 ◽  
Author(s):  
Andriy Kuzyshyn ◽  
Andriy Batig ◽  
Sergei Kostritsa ◽  
Julia Sobolevska ◽  
Vitalii Kovalchuk ◽  
...  
Keyword(s):  
Traffic Safety ◽  
Motor Vehicle ◽  
Stability Margin ◽  
Accurate Method ◽  
Railway Track ◽  
Rolling Stock ◽  
Operational Parameters ◽  
Wheel Pair ◽  
Rail Track ◽  
Safety Parameters

The problem of the interaction of rolling stock with the rail track has been analyzed in the present paper. It has been established that in the process of transport science development a number of methods for determining the causes of wheel pairs derailment are developed, which, in a varying degree, take into account the peculiarities of their interaction. The problem of choosing the most accurate method for estimating the causes of rolling stock derailment becomes more complicated because of the lack of sufficient experimental data that would allow us to verify the adequacy of the models. The indicators of stability of the wheel against derailment, which are used on the railways of Ukraine and Europe, have been examined. Their dependences on the speed of movement were derived. It has been established that the increase of the speed of motion leads to the increase of the interaction power of the rolling stock with the rail track, which may, under certain operational parameters, provoke its derailment. As a result of the calculations, it has been shown that the use of norms for car design and calculation used on Ukrainian railways can lead to an inadequate estimation of traffic safety parameters, since it does not take into account the unevenness of the railway track. It has been established that the requirements of BS EN 14363: 2005 European norms are stricter in comparison with the norms for calculation and evaluation of the bearing elements strength and dynamic qualities of motor-vehicle rolling stock used on Ukrainian railways. A comparison of the experimentally and theoretically calculated values of the stability margin coefficient against wheel derailment of the first wheel pair of the diesel train car was carried out.

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