Summary. The article presents the research results of economic feasibility of trains' breaking-up order control at marshalling yards. The article objective was to determine the area of rational use of trains' breaking-up order model, formalized in the form of stochastic programming problem. As a effectiveness criterion of trains' breaking-up order operating costs of marshalling yard were used, including the costs associated with cars' and locomotives' dwell time on the station and its approaches, as well as costs associated with additional shunting work. With the help of simulation modeling the dependence was obtained, describing the impact of trains' arrival forecasting error and processed car volumes on reducing operating costs of the marshalling yards through the trains' breaking-up order control. The studies enable us to establish the requirements for the accuracy of information support of operational planning tasks, which is necessary to achieve the desired economic effect of the trains' breaking-up order control.
In modern practice of operating under traffic safety conditions, the traffic light signal must be transmitted to the locomotive that moves to it, and duplicate in the driver’s cab. However, this communication channel is not protected from external interference. In order to prevent the occurrence of code failure, it is necessary to create conditions under which the automatic locomotive signalling system will distinguish between signals with useful information, from signals with false information. The best way to solve this problem at the first stage is to model the devices. Using the simulation tools of graphical environment of simulation modelling Simulink from Matlab software environment, the software model of the communication channel between the railroad and the input devices of automatic locomotive signalling system was constructed. The created mathematical model with the actual parameters allows us to obtain diagnostic signs of a proper condition, on the basis of which the research is aimed at the identification, recognition and definition of various types of malfunctions, failure, damages and defects in the work of the constituent elements of the system and the signal transmission channel of the automatic locomotive signalling system.
Purpose. Investigation and analysis of the hanger arrangement and the structural stability of a Network arch bridge -a tied-arch bridge with inclined hangers that cross each other at least twice. It is also necessary to make a comparative analysis with other types of hanger arrangements. Methodology. The authors in their research investigated a large number of parameters to determine their influence in the force distribution in the arch. Eventually they determined optimal values for all parameters. These optimal values allowed developing a design guide that leads to optimal arch design. When solving this problem, the authors used three-dimensional finite element models and the objective was to determine the most suitable solution for a road bridge, with a span of 100 meters, consisting of two inclined steel arches, located on a road with two traffic lanes, subjected to medium traffic. The virtual prototype of the model is performed by finite element simulator Midas Civil. Findings. In this study, for the bridge deck, a concrete tie appears to be the best solution considering the structural behavior of network arches, but economic advantages caused by easier erection may lead to steel or a composite bridge deck as better alternatives. Design requirements and local conditions of each particular bridge project will decide the most economic deck design. Originality. To ensure passenger comfort and the stability and continuity of the track, deformations of bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic.A network arch bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties. Practical value. Following the study design advice given in this article leads to savings of about 60 % of structural steel compared with conventional tied arch bridges with vertical hangers.
This work aims to solve one of the essential problems in railway transport – control over the position of moving units within the race. A method of constant monitoring of the track circuit with a determination of the coordinate of the train shunt placement in the shunt mode of working is proposed to solve this problem. Since the model includes the primary parameters of the track circuit, which may change their values over time, it is suggested to determine them in another (normal) working mode of the track circuit. Therefore, according to the proposed model, the secondary and primary parameters of the track circuit are first determined in the track circuit's normal work mode. Next, already in the shunt mode of its work, the obtained parameters are used to determine the coordinates of the moving unit. According to this method, firstly, the work mode of the track circuit is determined, which consists in determining the state by its input impedance. This step is performed in two stages. In the first stage, based on the state of the track relay, the fact that the track circuit doesn't work in normal mode is verified. In the second stage, the shunt mode is separated from the control mode by the value of the track circuit input impedance. In the shunt mode of the track circuit operation, the coordinate and, if necessary, the speed and acceleration of the moving unit located within the given track circuit are determined. In the normal mode of the track circuit line operation, the values of its secondary parameters are specified based on the measured values of current, voltage, and phase shift between them. This operation is performed to increase the precision of the speed and acceleration determination by solving an inverse problem. In the control mode of the track circuit operation, it is possible to determine the coordinates of damage. This method does not require a significant volume of calculations. It makes it possible to determine the secondary parameters of the track circuit and through them, the resistance of its insulation. Using this method makes it possible to determine the distance and, if necessary, the speed and acceleration of a moving unit within the track circuit. The resulting parameters can be used for positioning moving rolling stock on runs between stations. The application of this method can also be useful in sections of the railway crossings approach to implement a fixed warning time. In addition, thanks to the use of the outlined model, in the control mode of the track circuit operation, is possible to determine the damage coordinate. It will make it possible to reduce the time spent on damage detection and elimination.
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