scholarly journals Permissible Values of the Dynamic Impact of the Rolling Stock on the Railway Track in the Case of Axle Load Increase

2021 ◽  
pp. 15-23
Author(s):  
О. M Patlasov ◽  
Y. M Fedorenko
Keyword(s):  
Dynamic Effect ◽  
Field Measurements ◽  
Experimental Tests ◽  
Railway Track ◽  
Rolling Stock ◽  
Actual State ◽  
Dynamic Force ◽  
Dynamic Impact ◽  
Railway Line ◽  
The Impact

Purpose. The study is aimed at determining experimentally the values of the parameters characterizing the dynamic effect of rolling stock on the railway track, substantiating the maximum permissible (limiting) values. Methodology. To investigate the interaction between the track and the rolling stock, the devices to record various physical processes were installed on the experimental sections. The devices were installed in 8 sections along the outer railway line. To establish the actual state of the track, field measurements were carried out in accordance with the Program and research methodology. Findings. According to the results of experimental tests of the impact on the track, it was revealed that the average vertical loads, and, accordingly, the average vertical deformations, under the cars with an axle load of up to 25 tf/axle are higher than that under the cars with an axle load of up to 23.5 tf/axle by 8 percent. The maximum vertical loads under the cars with an axle load of 25 tf/axle exceeded the average loads by 10.0 tf, and under the cars with an axle load of up to 23.5 tf/axle exceeded the average values by 12.8 tf. During the tests, no cars were found in which the vertical dynamic force exceeds 20 tf, and the horizontal force exceeds 10 tf. Therefore, the norms of permissible dynamic impact can be taken in accordance with the Regulations on Preventive Maintenance and Repair Track Work on the Railways of Ukraine. Originality. The authors conducted a study to assess the dynamic characteristics of the interaction of track and rolling stock, in particular the stresses in the edges of the rail base, vertical and horizontal forces from the wheels of rolling stock. Practical value. On the basis of the results obtained, it is possible to estimate the permissible values of the dynamic effect of the rolling stock on the railway track to substantiate the need to change the standards for the material consumption of the track superstructure and labor. In turn, this will make it possible to plan the repair and track periods more economically and according to the actual indicators of the state of the track superstructure.

scholarly journals Railway Track Stress–Strain Analysis Using High-Precision Accelerometers

2021 ◽  
Vol 11 (24) ◽  
pp. 11908
Author(s):  
Alexandr Avsievich ◽  
Vladimir Avsievich ◽  
Nikita Avsievich ◽  
Dmitry Ovchinnikov ◽  
Anton Ivaschenko
Keyword(s):  
High Precision ◽  
Strain Analysis ◽  
Railway Track ◽  
Rolling Stock ◽  
Mathematical Methods ◽  
Stress Strain ◽  
Technical Parameters ◽  
The Impact ◽  
The Internet Of Things ◽  
Track Line

We propose a new approach for railway path diagnostics on the basis of track line stress–strain analysis using the data provided by high-precision accelerometers. This type of sensor provides sufficient accuracy with lower costs, and enables the development of a railway digital twin, according to the concept of the Internet of Things. The installation of sensors on a railway track along its entire length allows real-time monitoring of the states of the technical parameters of the railway track, and using mathematical methods to evaluate its wear on the basis of constantly received data. This paper presents an original 3D model of a railway track line and the results of its analysis using a finite element method. To test the model, we performed an analysis of the normal stresses and deformations in the elements of a railway track by simulating the impact of rolling stock on a section of a railway track with intermediate rail fastenings, ZhBR-65SH. The research results were probated and tested at the testing ground of the Kuibyshev branch of Russian Railways, the Samara track. The proposed approach makes it possible to determine the load of the track, and knowing the movement of the rail, to calculate the structural stress in the elements of the railway track, to constantly monitor the parameters of the slope and rail subsidence.

Ultrasonic waves for effective assessment of wheel-rail contact anomalies

2005 ◽  
Vol 219 (2) ◽  
pp. 79-90 ◽  
Author(s):  
M Pau
Keyword(s):  
Contact Area ◽  
Ultrasonic Method ◽  
Experimental Tests ◽  
Ultrasonic Waves ◽  
Rolling Stock ◽  
Future Application ◽  
Real Contact Area ◽  
Railway Line ◽  
Rail Systems ◽  
Effective Assessment

Ultrasonic waves are routinely used in the railway industry to supply information about integrity of wheels, rails, and axles for both quality control assessment (during the production process) and ‘in situ’ when the rolling stock has to be periodically checked for maintenance purposes. Nevertheless, recently the authors proposed a different application of this technique which, although employing the same kind of equipment as a standard NDE control, is able to investigate the main features of the wheel-rail contact interface such as nominal contact area, real contact area, and contact pressure distribution. On the grounds of the promising results obtained in the previous tests, this study proposes a further practical approach to common problems of wheel-rail contact that possibly affect the regular development of railway operations. To this end, a number of wheel-rail systems were altered by artificially producing several kind of defects on their surfaces and thus obtained couplings were then analysed by the ultrasonic method in order to assess the capability of the technique to faithfully reproduce the modification introduced in the contact patch. The results of the experimental tests allow us to state that the ultrasonic analysis of wheel-rail contact interfaces can be effectively employed to detect any sort of irregularities potentially present due to normal operations, and foresees a future application of the method as a tool to monitor critical points of a railway line in order to ensure significant improvements in safety conditions.

scholarly journals Application of the Bezgin Method to estimate dynamic impact forces and judge the conditions for ballast pulverization and slab cracking due to abrupt and rapid changes in railway track profile

2021 ◽  
Author(s):  
Erdem Balcı ◽  
Niyazi Özgür Bezgin
Keyword(s):  
Experimental Studies ◽  
Rate Of Change ◽  
Railway Track ◽  
Rolling Stock ◽  
Structural Domain ◽  
Numerical Techniques ◽  
Dynamic Impact ◽  
Accurate Analysis ◽  
Impact Forces ◽  
Track Stiffness

Dynamic impact forces occur on railway tracks due to the presence of roughness of the track and the wheel and relate to the train speed and the rate of change of roughness. Variations in track profile and track stiffness and variations in wheel circularity are the causes of roughness. Quantification of the dynamic impact forces is not an easy task due to the complexity of the mechanics of the rolling stock interaction with the railway track. A number of experimental studies have led to an understanding of the dynamic impact forces, yielding a set of conservative and case-specific empirical equations. There are also many calculation-intensive numerical techniques, relying on iterative calculations seeking to converge to a state of temporary equilibrium for the analyzed structural domain within small-time increments. These techniques provide detailed and valuable information for the stresses that develop within the many components of the railway track. However, such numerical techniques rely on expensive computational tools that require experienced users to apply and interpret their results. The sheer amount of representative structural and material data input required to define the analyzed structural domain of the railway track properly is also an important task to accomplish in order to conduct a meaningful analysis. The second author developed a simple analytical method that can provide an accurate analysis for the dynamic impact forces on any railway track relying on track stiffness as the only mechanical railway track parameter. This paper introduces an ongoing study led by the second author and provides an insight into how a designer or a track maintainer can apply the Bezgin Method to estimate dynamic impact forces that may occur in rail-ends and within turnouts. This paper will also discuss how one can judge the conditions for ballast pulverization or slab cracking should these conditions exist.

scholarly journals Assessment of the impact of vibrations on the track surface from impact loads

2019 ◽  
Vol 252 ◽  
pp. 01007
Author(s):  
Michał Jukowski ◽  
Krzysztof Śledziewski ◽  
Mateusz Hypki
Keyword(s):  
Railway Track ◽  
Railway Vehicle ◽  
Impact Loads ◽  
Vibration Acceleration ◽  
Dynamic Impact ◽  
Limit Condition ◽  
Ground Conditions ◽  
Track Surface ◽  
The Impact ◽  
Construction Works

Dynamic development of the linear infrastructure in Poland directly contributed to the increase in the number of engineering sites and facilities. Due to ground conditions and values of exploitation loads, in some cases bridge supports must be placed on foundation piles, the method of execution of which may cause significant dynamic impact on the structures located in the close vicinity. The paper assesses the impact of dynamic actions resulting from impact loads during impact pile driving of FRANKA piles with the use of a guide pipe on the railway track surface, on which there is continuous railway vehicle traffic. The tests have shown that the serviceability limit condition has been met and that the construction works do not result in exceeded values of vibration acceleration.

scholarly journals Dynamic Wheel-Rail Force-Based Track-Irregularity Evaluation for Ballasted Track on Serviced Railway by Adjacent Excavation

2021 ◽  
Vol 12 (1) ◽  
pp. 375
Author(s):  
Jung-Youl Choi ◽  
Dong-Ryong Park ◽  
Jee-Seung Chung ◽  
Sun-Hee Kim
Keyword(s):  
Impact Load ◽  
Field Measurements ◽  
Interaction Force ◽  
Wheel Load ◽  
Track Geometry ◽  
Railway Line ◽  
Before And After ◽  
Track Irregularity ◽  
The Impact ◽  
Track Irregularities

This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation between the track irregularities and the Wheel-Rail interaction force. In this way, we highlight the necessity for load-based track-irregularity-management methods. The analyzed results show that the maximum dynamic wheel load was measured in the range of approximately 10 m before and after the location where the maximum track irregularities occurred, and that even if the maintenance criteria of track irregularities were satisfied, the design dynamic wheel load could still be exceeded depending on the train speed, thus indicating that track damage can be caused by the impact load.

scholarly journals Life Cycle Cost Evaluation of Noise Control Methods at Urban Railway Turnouts

2016 ◽  
Author(s):  
Rodrigo Tavares De Freitas ◽  
Sakdirat Kaewunruen
Keyword(s):  
Life Cycle ◽  
Life Cycle Analysis ◽  
Cost Evaluation ◽  
Railway Track ◽  
Rolling Stock ◽  
Noise And Vibration ◽  
Impact Noise ◽  
Wide Range ◽  
Mitigation Methods ◽  
The Impact

The railway industry focus in the past years was to research, find and develop methods to mitigate noise and vibration resulted from wheel/rail contact along track infrastructure. This resulted in a wide range of abatement measures that are available for the professionals of the industry today. However, although there are many options in the market, their practical implementations depend upon general constraints that affect most technological application in the engineering world. The progression of these technologies have facilitated the selection of more adequate methods for each best case scenario, but further studies are ought to be made to proper assess if each one is fit for their purpose. Every method implementation must be analyzed through budget and timeframe limitations, which includes building, maintenance and inspection costs and time allocation, while also aiming to meet different benefits, such as environmental impact control and wear of the whole infrastructure. There are several situations and facilities in a railway project design that need noise and vibration mitigation methods and each design allocates different priorities for each one of them. Traditionally the disturbance caused by railways to the community are generated by wheel/rail contact sound radiation that expresses in different ways, depending on the movement of the rolling stock and track alignment, such as rolling noise, impact noise and curve noise. More specifically, in special trackworks such as turnouts, the main area of this study, there are two noises types that must be evaluated: impact noise and screeching noise. With respect to the second, it is similar to curve squeals and, being such, its mitigation methods are to be assigned as if it was to abate curve squeal in turnouts and crossings. The impact noise on the other hand, emerges from the sound made by the rolling stock moving through joints and discontinuities (i.e. gaps) that composes these special components of a railway track. A life cycle analysis is therefore substantial for this reality and in this case will be applied to Squeal and Impact Noise on Special Trackwork. The evaluation is based on a valid literature review and the total costs were assumed by industry reports to maintain coherency. The period for a life cycle analysis is usually of 50 years, hence it was the value assumed. As for the general parameters, an area with high density of people was considered to estimate the values for a community with very strict limits for noise and vibration.

scholarly journals Elastic characteristics of the underrail base of a ballastless railway track

2021 ◽  
Vol 2021 (4) ◽  
pp. 469-479
Author(s):  
Alexey F. KOLOS ◽  
◽  
Ksenia I. IVANOVA ◽  
Keyword(s):  
Practical Importance ◽  
Operating Conditions ◽  
Railway Track ◽  
Rolling Stock ◽  
Relative Stiffness ◽  
Ballastless Track ◽  
Full Scale Tests ◽  
The Impact ◽  
Track Modulus ◽  
Elastic Characteristics

Objective: Experimental determination track modulus and the coeffi cient of relative stiffness of underrail base and the rail, which are the main elastic characteristics that determine the stresses in the structural elements of track superstructure under the impact force from the train. The values of these parameters for a track with a ballast layer are well studied, in contrast to a ballastless track. Comparison of the elastic characteristics of a ballastless railway track with analogs of a track on ballast, as well as an assessment of their effect on the stress-strain state of the superstructure elements of a ballastless track. Methods: When carrying out full-scale tests, strain-gauge methods for measuring stresses in the elements of the track superstructure were used. The obtained values were processed by the methods of mathematical statistics. One statistical series included the values of stresses corresponding to one type of rolling stock, fi xed axle load and train speed, changing by no more than 10 km/h. The probability level in processing the results was taken in all cases equal to 0,994. Results: The values of track modulus and the coeffi cient of the relative stiffness of the underrail base and the rail were obtained for a ballastless structure of the RHEDA 2000 type. Practical importance: The results allow us to consider the rail as a beam lying on a solid elastic foundation in relation to the ballastless track and use the existing calculation methods for the design of ballastless track structures depending on the operating conditions.

scholarly journals DYNAMIC MODELLING OF HIGH SPEED BALLASTED RAILWAY TRACKS: ANALYSIS OF THE BEHAVIOUR

2016 ◽  
Author(s):  
Santos Sánchez-Cambronero ◽  
Inmaculada Gallego ◽  
Ana Rivas ◽  
Julián Lajara
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Dynamic Modelling ◽  
Dynamic Effect ◽  
Railway Track ◽  
Moving Loads ◽  
The Finite Element Method ◽  
Vertical Stiffness ◽  
Railway Line ◽  
Moving Train

The aim of the paper is to present a numerical model for a ballasted railway track that includes the dynamic effect of a moving train load and predicts the values of the vertical stiffness of the infrastructure. This model is therefore deemed to be a tool for the evaluation of the state of the track during service situations as well as a predictive model of the behaviour of the system. Consequently, it will be very useful when sizing the cross section of a new railway line is required.The main modelling tool is the finite element method. In regard to this, the application of damping elements to avoid the elastic wave reflection on the boundaries of the numerical domain will be studied. The proposed dynamic analysis consider the change in time of the value of the train load, but not the change in position along the tracks.In the end, a set of suggestions for the numerical model with moving loads will be summarize aiming for the mitigation of the unusual behaviour of the contact surface between the ballast and the sleepers.DOI: http://dx.doi.org/10.4995/CIT2016.2016.4218

scholarly journals EXPERIMENTAL INVESTIGATION ON DYNAMIC BEHAVIOUR OF HEAVY-HAUL RAILWAY TRACK INDUCED BY HEAVY AXLE LOAD

Transport ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 351-362 ◽  
Author(s):  
Zhiyong Shi ◽  
Kaiyun Wang ◽  
Dawei Zhang ◽  
Zaigang Chen ◽  
Guanghao Zhai ◽  
...  
Keyword(s):  
Dynamic Behaviour ◽  
Experimental Tests ◽  
Railway Track ◽  
Track Structure ◽  
Dynamic Force ◽  
Speed Range ◽  
Heavy Haul ◽  
Load Effects ◽  
Heavy Haul Railway ◽  
Made In

The damage to the track structure and the influence to the line deformation have greatly deteriorated with the increase of the axle load compared with that of the ordinary trains. However, there is a paucity of experimental research on the dynamic influence of the heavier haul freight trains on the railway tracks. The objective of this study is to investigate the dynamic behaviour of heavy-haul railway track induced by heavy axle load by field experimental tests. The wheel–rail dynamic force, the track structure dynamic deformation and the track vibration behaviour are measured and analysed when the train operates in the speed range from 10 to 75 km/h and the axle load of vehicles varies from 21 to 30 t. Comparisons between the results for the axle conditions of 25 and 30 t are made in this paper to reveal the axle load effects. It is demonstrated that part of the indicators reflecting the dynamic behaviour of the railway track increases approximately linearly with the train running speed and axle load, while others are influenced negligibly

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