About Longitudinal Dynamics of Classical Passenger Trains during Braking Actions

2013 ◽  
Vol 378 ◽  
pp. 74-81 ◽  
Author(s):  
Cătălin Cruceanu ◽  
Camil Ion Crăciun
Keyword(s):  
Traffic Safety ◽  
Numerical Examples ◽  
Longitudinal Dynamics ◽  
Braking System ◽  
Dynamic Forces ◽  
Passenger Trains

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.

Distribution of Longitudinal Forces in the Body of Passenger Trains

2015 ◽  
Vol 809-810 ◽  
pp. 1175-1180 ◽  
Author(s):  
Camil Ion Crăciun ◽  
Mădălina Dumitriu
Keyword(s):  
Numerical Simulations ◽  
Mechanical Model ◽  
Rigid Bodies ◽  
The Body ◽  
Nonlinear Characteristic ◽  
Braking System ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Passenger Trains ◽  
Over Time

The distribution and the size of longitudinal dynamic forces that develop in the train body found in braking system are influenced by the length of the train. To determine these forces, it is used a mechanical model consisting of rigid bodies, representing the train vehicles, connected by elastic and damping elements with the nonlinear characteristic that shapes the buffer and draw-gear. The results based on numerical simulations highlight the emergence of dynamic longitudinal forces during braking, their evolution over time and the distribution of maximum compression and stretching forces that develop in buffer and draw-gear devices, for different lengths of the passenger train.

Analysis of the degree of infl uence of the removal rate of passenger trains for the passage of freight trains on double-track sections

Innotrans ◽  
2021 ◽  
pp. 59-64
Author(s):  
Marufjan Kh. Rasulov ◽  
◽  
Masudjon N. Masharipov ◽  
Zhasurbek Ya. Abdullayev ◽  
◽  
...  
Keyword(s):  
Traffic Safety ◽  
Removal Rate ◽  
Mutual Arrangement ◽  
Calculation Formula ◽  
Passenger Trains ◽  
Railway Capacity ◽  
Double Track

The article is devoted to the analysis, calculations, and methods of determining the removal rate and the degree of its influence in case of mutual arrangement of freight and passenger trains on the traffic schedule. The article summarizes the results of mass analytical calculations for determining the removal rate, and provides calculations based on experimental train schedules. The calculation of the removal rate is carried out in a new way, which takes into account the factors that guarantee traffic safety and the most complete use of the available railway capacity, and also offers a calculation formula.

Researches on the Behavior of the Supporting Structure of Railway Traction Vehicles under the Effect of Shock Dynamic Forces

2014 ◽  
Vol 659 ◽  
pp. 237-242
Author(s):  
Ioan Sebesan ◽  
Gabriel Popa ◽  
Marius Adrian Spiroiu
Keyword(s):  
Traffic Safety ◽  
Rolling Process ◽  
Railway Vehicle ◽  
Frontal Impact ◽  
Stick Slip ◽  
Driving System ◽  
Supporting Structure ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Railway Traction

During circulation the railway vehicle is subjected to the action of dynamic forces under the effect of shocks that appear in the driving system caused by stick slip phenomenon, dynamic forces arising from the rolling process when the wheelset is passing over accidental vertical unevenness of the track and also longitudinal dynamic forces occurring in the case of buffering, respectively those caused by frontal impact (the crash forces). The present paper presents the mechanical and mathematical models which are underlying the evaluation of the magnitude of these forces as well as their effects on the resistance of supporting structure of the vehicle and on traffic safety.

A Method to Obtain a Generalized Model of the Pressure Evolution within the Braking System of a Vehicle

2013 ◽  
Vol 837 ◽  
pp. 434-439 ◽  
Author(s):  
Marin Marinescu ◽  
Radu Vilau ◽  
Marian Truta ◽  
Octavian Fieraru
Keyword(s):  
Traffic Safety ◽  
Road Network ◽  
Technical Condition ◽  
Parametric Models ◽  
Fast Method ◽  
Braking System ◽  
Military Vehicles ◽  
Technical Status ◽  
National Road ◽  
The Military

Military vehicles have to travel, at least from time to time, on the national road network. Whenever that happens, the legal requirements have to be met with respect to the systems that contribute to the traffic safety. One of these systems is the braking system. On the other hand, most of the military vehicles arent that up-to-date that the rest of the traffic partners are. Therefore, a military automotive engineer should have at hand a fast method to diagnose the technical status of the braking system even the checked vehicle is rather old. It would be also even better if the faulty party were accurately identified. The paper aims at providing a method helps the diagnosing teams to quickly compare the behaviour of an actual vehicle braking system status with a general model that had been acquired by tests. Since nobody provided that kind of information during 70s, our model derived from a large number of tests that have been performed on good technical condition vehicles. Key words: vehicle braking system, parametric models, data-based models.

scholarly journals TECHNOLOGICAL MEASURES OF FOREFRONT ROAD IDENTIFICATION FOR VEHICLE COMFORT AND SAFETY IMPROVEMENT

Transport ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 363-372 ◽  
Author(s):  
Vidas Žuraulis ◽  
Vytenis Surblys ◽  
Eldar Šabanovič
Keyword(s):  
Image Analysis ◽  
Traffic Safety ◽  
Laser Scanning ◽  
Road Surface ◽  
The Road ◽  
Emergency Braking ◽  
Braking System ◽  
Safety Improvement ◽  
Road Friction ◽  
Surface Irregularities

This paper presents the technological measures currently being developed at institutes and vehicle research centres dealing with forefront road identification. In this case, road identification corresponds with the surface irregularities and road surface type, which are evaluated by laser scanning and image analysis. Real-time adaptation, adaptation in advance and system external informing are stated as sequential generations of vehicle suspension and active braking systems where road identification is significantly important. Active and semi-active suspensions with their adaptation technologies for comfort and road holding characteristics are analysed. Also, an active braking system such as Anti-lock Braking System (ABS) and Autonomous Emergency Braking (AEB) have been considered as very sensitive to the road friction state. Artificial intelligence methods of deep learning have been presented as a promising image analysis method for classification of 12 different road surface types. Concluding the achieved benefit of road identification for traffic safety improvement is presented with reference to analysed research reports and assumptions made after the initial evaluation.

scholarly journals Modeling the longitudinal dynamics of electric multiple units with Xcos/Scilab software

2021 ◽  
Vol 1199 (1) ◽  
pp. 012066
Author(s):  
J Jackiewicz
Keyword(s):  
Dynamic Modeling ◽  
Computer Simulations ◽  
Longitudinal Dynamics ◽  
Longitudinal Dynamic ◽  
Vibration Protection ◽  
Dynamic Forces ◽  
Multiple Units

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.

EFFICIENCY ASSESSMENT OF BRAKING EQUIPMENT OPERATION IN INNOVATION FREIGHT CARS

2021 ◽  
Vol 2021 (3) ◽  
pp. 46-53
Author(s):  
Elena Rozhkova
Keyword(s):  
Traffic Safety ◽  
Defect Formation ◽  
Least Squares Method ◽  
Normal Operation ◽  
Design Factor ◽  
Wheel Pair ◽  
Braking System ◽  
Freight Car ◽  
Train Length ◽  
Definition Of

The object of researches is brake systems of innovation freight cars. The work purpose consists in the assessment of braking system effectiveness in innovation freight cars and in standard ones at different operation modes. The scientific novelty consists in the definition of the dependence of a slide block depth on the length of wheel pair skidding motion and braking distance dependence upon car speed. During the work there was carried out a retrospective analysis of cases with traffic safety violation connected with the formation of excessive sliders in freight cars in organized trains because of the violation of braking equipment normal operation. By means of the least-squares method there was obtained a linear equation defining the dependence of slider depth upon the skidding length of a wheel pair. As a result of the work there were defined parameters of defect formation on freight car wheels at their skidding, the calculations of braking system efficiency in different freight cars were carried out. In the course of the analysis of freight car braking efficiency there are obtained equations of braking length in the accepted range of speeds at the beginning of braking for empty and loaded states. Minimum values of the design factor of braking block pressing in translation to a train length of 200 shafts in the empty state were 0.2256 for a speed of 40km/h, in the loaded one – 0.1781 for a speed of 120 km/h at the standard values 0.22 and 0.14 respectively. By means of calculations and experiments it is proved that composite braking block pressing force on a shaft exceeds 4tf/shaft, and that of cast-iron – 10tf. Accordingly, a car with the shaft load of 25 tf/shaft and accepted parameters of a braking system may be operated up to the speeds of 120 km/h inclusive without limitations.

Influence of Speed Bumps Design on Vehicle Safety

2011 ◽  
Author(s):  
D. Garci´a-Pozuelo ◽  
E. Olmeda ◽  
A. Gauchi´a ◽  
V. Di´az
Keyword(s):  
Traffic Safety ◽  
Experimental Testing ◽  
Simulation Software ◽  
Motor Vehicles ◽  
Vehicle Safety ◽  
Vehicle Velocity ◽  
Dynamic Forces ◽  
Different Types ◽  
Proper Design ◽  
Real Vehicle

During a journey motor vehicles are forced to overcome different types of irregularities in the pavement. Such irregularities can be random or introduced for a specific purpose, such as asphalt protrusions and transversal bands of rubber, which have been installed into all sorts of avenues and roads open to traffic. Generally, these elements are included in a stretch of road to slow down the vehicle velocity at certain sites, such as pedestrian crossings. However, the influence of speed bumps installed shows other additional effects which must be studied to ensure the safety of vehicles and pedestrians. In some cases, it is found that, passing over ridges and transverse bands at a speed below the limit defined by law, the vehicle is damaged or the tires lose grip with the pavement, precluding any kind of braking or turning maneuvers. Such phenomena indicate that this element is not properly sized, or the placement is not appropriate, becoming counterproductive for traffic safety. In spite of the importance of these consecuences derivated from these elements they haven’t been studied deeply enough and there are very few paper about this subject. In order to analyze the actions generated by the overcome of these irregularities on the different components of the vehicle and its occupants, the problem has been studied not only using computer simulation but also by means of experimental testing on a real vehicle where accelerometers were installed in order to check the severity of the bumps. CarSimTM has been the simulation software used to calculate vehicle dynamic forces on the tires and suspension system and the accelerations and displacements that are applied to the vehicle. To characterize the behavior of a vehicle when is driven over one of these obstacles, it is necessary to study several parameters such as: speed, geometry and dimensions of the bump, and the type of vehicle and its suspension. From this information it is possible to establish a set of guidelines for the proper design and installation of speed bumps in different roads.

scholarly journals Optimization of the design of relay valves for rail vehicles braking systems in the context of train traffic safety

2019 ◽  
Vol 294 ◽  
pp. 03013
Author(s):  
Sylwin Tomaszewski ◽  
Franciszek Tomaszewski ◽  
Włodzimierz Stawecki ◽  
Patryk Urbański ◽  
Mariusz Far ◽  
...  
Keyword(s):  
Traffic Safety ◽  
Low Temperatures ◽  
Control Method ◽  
High Reliability ◽  
Operational Reliability ◽  
Design Solution ◽  
Structural Factors ◽  
Factors Affecting ◽  
Braking System ◽  
Rail Vehicles

The article presents the functions of the relay valve and its place in brake systems of rail vehicles. The relay valve were divided according to their type, the structure and principle of their operation were discussed, and examples of rail vehicles and modules in which relay valves are installed are presented. Because of their function in braking systems the relay valves should be characterized by high reliability and correct carrying out the tasks in the braking system of rail vehicles. The article describes selected structural factors affecting the operation of the relay valve and which are important for ensuring the safety of train traffic. Such factors are the lubricants used in the relay valves and the way of controlling it simultaneously with two signals with the function of an alternative that eliminates unreliable elements of the braking system. The analysis of the test results of the lubricant parameters and the testing of the relay valves on the test bench showed that the correctness of the relay valves depends essentially on the properties of the lubricant used, especially at low temperatures. On the basis of the tests carried out, a grease was selected that at low temperatures meets the criteria for correct and reliable operation of relay valves in rail vehicles. In terms of the control method, a comparison of two control signal delivery systems to the relay valve has been made, a new design solution is presented that ensures greater operational reliability and thus greater safety of the train traffic.

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