DEVELOPMENT OF SOFTWARE FOR AUTOMATION OF CALCULATIONS OF RAIL CIRCUITS

ABSTRACT

Interval train systems play an important role in ensuring safe and efficient railway transportation. They ensure smooth train schedules and maintain safety and quality for both passenger and freight traffic. Development and implementation of these systems requires advanced engineering and scientific methods, including mathematical modeling. This article discusses a mathematical model for railway circuits implemented using two methods: creating a library for MatLab Simulink and implementing a specialized application using the Python 3.11 programming language to calculate rail circuits.

АННОТАЦИЯ

Системы интервального движения поездов играют важную роль в обеспечении безопасной и эффективной работы железнодорожного транспорта. Они обеспечивают бесперебойную исполнение графика движения поездов и поддерживают безопасность и качество как пассажирских, так и грузовых перевозок. Разработка и внедрение данных систем требуют передовых инженерных и научных методов, включая математическое моделирование. В данной статье рассмотрена математическая модель рельсовых цепей, реализованная двумя методами: созданием библиотеки, для программного обеспечения MatLab Simulink и реализацией специализированного приложения, для расчёта рельсовых цепей, с помощью языка программирования Python v.3.11.

Keywords: Rail circuits, mathematical model, operating modes of rail circuits, four-pole method, Python, HTML, CSS, JavaScript, MATLAB, Simulink, «Olga» library, «Nadejda» program software, software.

Ключевые слова: Рельсовые цепи, математические модели, режимы работы рельсовых цепей, метод четырёхполюсников, Python, HTML, CSS, JavaScript, MATLAB, Simulink, библиотека «Ольга», программное обеспечение «Надежда», программное обеспечение.

Introduction: The rail circuit sensor is the most commonly used type on Uzbekistan's railways. Unlike other types of sensors, such as the electronic axle-counting system, the rail circuit sensors can monitor the health of the tracks and prevent train accidents if a track becomes damaged. Work on improving rail circuit sensors has not stopped, and efforts in this area are ongoing due to the evolution of train technology and the development of railway infrastructure. Therefore, one of the most important requirements in the design of rail circuits is the accuracy of their calculations.

Rail circuits comprise power sources, dependent devices and railway tracks (fig. 1).

Fig. 1: Schematic diagram of a railway circuit

The railway system functions in one of five modes:

• Default mode – no trains are on the track and the tracks are undamaged. A dependent device receives power from a power source. The track is prepared to receive a train.
• Shunting mode – a train follows the track, with current travelling along the axle wheels. A relay is turned off because there isn’t enough current to operate it.
• Monitoring mode - in this mode, the receiver does not receive current because the track is damaged. This mode helps to prevent dangerous situations, such as collisions.
• Short circuit protection mode - when a train enters a section of railway track, the current may be high enough to damage the components of the track circuit. To prevent this, it's important calculating the resistance of the circuit, which helps protect the electrical equipment at the power supply point.

ALSN mode - this is the condition of a healthy track circuit, in which a sufficient amount of current is generated on the track to transmit signals to the locomotive.

The purpose of the research presented in this article is creating software that will enable more accurate calculations and development a program for analyzing rail circuits.

Method of calculating. Rail circuits computing is produced by the four-pole method under the worst conditions. [1, p. 27] (table 1) It means division of them into particular elements (rail line, power and receive points). After every element replaced with four-pole scheme (fig. 2) [1, p. 326].

Table 1

The worst conditions of working of rail circuit

Figure 2. Scheme of rail circuit’s math model.

Quadripoles of power  and receive  points consist of small four-poles of different electrical elements (transformers, resistance and other). It is possible to write them in the form of matrix. Their multiplication gives values of point matrix elements (1, 2)

Quadripole of rail circuit  is calculated with formula (3):

where  – rail line quadripole [1, p. 326]

Rail line quadripole is calculated for other modes. For example, it coefficients for normal mode are found with next formulas (4, 5, 6)

where  - distribution coefficient (7),  – the wave resistance (8).

where  - the equivalent resistance of isolation () and pillar of high voltage contact line () (9).

Voltage () and current () on the power input is found with expressions (7, 8)

Where  and  is voltage and current of receiver (relay) input.

Results. Research of problems of rail circuits calculating shows some causes, why it is very difficult. Engineer must process very much information (operations with big complex numbers), during their calculations. As a result of the research conducted, 3 software products were created.

Library “Olga”. Program code realised for MatLab Simulink. The project was facilitated by studying the works of Russian scientists in this field. [2, p. 67] It allows to calculate 5 modes of crossing rail circuits. (fig. 3)

Functional nodes were programmed with C++ program language. Code of one of the blocks is displayed on the fig. 4. To build a mathematical model, it is enough to create library blocks in the Simulink application, according to the scheme, depending on the mode you choose. [3, p.165]

Program software “Nadejda”. [4, p. 22] It was developed for reasons, where installation MATLAB software is impossible. Program were powered with Python language (fig. 5). During the development, were used «numpy», «math» и «eel» libraries, for working with complex numbers, matrix and connection with front-end (executed with HTML, CSS, JS). The fragment of functional engine code is showed on fig. 6. Advantage of this software is user-friendly and intuitive interface [5] [6].

Figure 3. Functional blocks set of “Olga” library and rail circuit normal mode computing

Figure 3. Program code of the block of calculating of rail circuit coefficient in normal mode

The Complex Calculator telegram bot (https://t.me/Mr_I_complexBot)[7], created for automating the calculation of complex numbers. It functional perform some basic and trigonometric numerical operations.

Figure 3. Interface of “Nadejda” software

Figure 6. Program code of “Nadejda” software

The above mentioned programs has been highly appreciated by teachers and students. Nowadays, work is ongoing to integrate the software into the student training program.

Discussion. In a result of the research, software products have been developed that allow the calculation of rail circuits in various modes. These products have demonstrated high accuracy (up to four decimal places), a significant advantage over manual calculations. Additionally, the use of these products has resulted in a reduction in calculation time. For example, using Olga's library, the first mode of a rail circuit can be calculated in up to ten minutes, compared to one hour without the use of specialized tools. The “Nadejda” application, written in Python, further reduces the time to around five minutes per calculation. However, a limitation of the application is that it cannot calculate a rail circuit in critical or ALSN modes a result of the research, software products have been developed that allow the calculation of rail circuits in various modes.

Conclusion. In this article was given information about investigation of rail circuits calculation. In the abstract, the main reasons for the study are considered. The purpose of the work is given and the introduction substantiates the relevance and feasibility of the work. Modes of operation of rail chains are considered, and after that, a method of studying these chains is described and a mathematical model is given, with formulas for calculating the normal mode of a distillation rail chain. As a result of the research, three software products were developed, which were described and their feasibility was discussed. The results of the study could form the basis for the development of complete program software for rail circuits.

References:

1. V.S. Arkatov, YU.V. Arkatov, S.V. Kazeev, YU.V. Obodovskiy. Relsovyie tsepi magistralnyih jeleznyih dorog: spravochnik III izdanie, pererabotannoe i dopolnennoe – Moskva: Izdatelstvo «OOO Missiya-M», 2006 god – 496 p. – ISBN 978-5-903538-01-0. – Tekst: neposredstvennyiy (dlya uchebnikov i uchebnyih posobiy)
2. Leushin, V. B. Mashinnoe modelirovanie v issledovaniyah relsovyih tsepey: uchebnoe posobie / V. B. Leushin, G. R. Rahmetov. – Samara: «SamGUPS», 2012 – 166 p. – ISBN 978-5-98941-180-1 – Tekst: neposredstvennyiy.
3. Proizvodstvo. Texnologiya. Ekologiya – PROTEK’22: sbornik trudov Vserossiyskoy molodyojnoy nauchno-texnicheskoy konferentsii s mejdunarodnim uchastiyem (g. Moskva, 27–29 sentyabrya 2022 g.) / pod red. dots. Ye. V. Butrimovoy, prof. L. E. Shvartsburga. – Moskva : FGBOU VO «MGTU «STANKIN», 2022. – 352 s.: il. ISBN 978-5-7028-0749-2
4. «Student: nauka, professiya, jizn»: Materiali IX vserossiyskoy studencheskoy nauchnoy konferentsii s mejdunarodnim uchastiyem: V 4 ch. / Omskiy gos. un-t putey soobscheniya. Omsk, 2022. Ch. 1. 564 s.
5. Rukovodstvo po ispolzovaniyu Python-biblioteki NUMPY / [Electronic resource]. - Access mode: URL: https://pythonru.com/biblioteki/rukovodstvo-po-ispolzovaniju-python-biblioteki-numpy (access date: 06/05/2024).
6. Eel in Python / [Electronic resource]. - Access mode: URL: https://www.javatpoint.com/eel-in-python (access date: 07/05/2024).
7. pyTelegramBotAPI’s documentation/ [Electronic resource]. - Access mode: URL: https://pytba.readthedocs.io/en/latest/ (access date: 09/05/2024).