Optimization of the system for maintenance and repair of refrigerated cars

The railcar maintenance and repair system (MRS) includes scheduled repairs (major repairs) and routine repairs and maintenance between scheduled repairs (hereinafter referred to as inter-repair periods, or IRPs). This paper examines the MRS of refrigerated rail-cars for potential improvement. Based on an analysis of the existing repair system, the scheduled repair intervals are varied. An optimization problem is solved, in which the best combination of these intervals is determined based on the adopted criterion. This makes it possible to both improve the economic efficiency of railcar operation and extend its service life. A new term, "unit profit per mileage" (hereinafter referred to as UPM), is introduced, which denotes the ratio of the total profit from railcar operation to its overall service life. This indicator, characterizing the economic efficiency of railcar operation, will be adopted as a criterion for optimizing the MRS of refrigerated railcars.

1. Instructions for the technical maintenance of wagons in operation (instructions for wagon in-spectors) No. 808-2022 PKB CV approved by the Council for Railway Transport of the Common-wealth Member States by Protocol No. 77 of December 8, 2022. – Moscow : CENTERMAG, 2026. – 204 p. – ISBN 979-5-903030-49-0.

2. Ustich, P. A. Application of information technologies in the system of maintenance and repair of wagons / P. A. Ustich, A. A. Ivanov, F. A. Mazhidov // Automation. Modern technologies. – 2016. – No. 10 (50). – P. 29–38. – ISSN 0869-4931.

3. Modeling and optimization of the wagon repair system / A. V. Zyablov, S. V. Bespalko, P. S. Grigoriev, Yu. A. Kuznetsova // Railway transport. – 2021. – No. 2. – P. 64–66. – ISSN 0044-4448.

4. Shinkaruk, A. S. Optimization of the system of technical maintenance and repair of passenger cars / A. S. Shinkaruk, S. V. Bespalko // Transport engineering. – 2024. – No. 11 (35). – P. 64–70. – DOI 10.30987/2782-5957-2024-11-64-70.

5. Wagon fleet : a textbook for higher education in-stitutions of railway transport / V. A. Ivashov, M. V. Orlov, P. A. Ustich [et al.] ; edited by P. A. Ustich. – Moscow : Route, 2003. – 560 p. – ISBN 5-89035-082-X.

6. Polshchikov, A. D. On the problem of organizing the system of maintenance and repair of freight cars in modern conditions of operation of the carriage industry / A. D. Polshchikov, A. A. Ivanov // Infra-structure and operation of land transport : proceedings of the International student scientific and practical conference : in 2 parts, Nizhny Novgorod, April 10, 2019 / Branch of Samara State Transport University in Nizhny Novgorod. – Nizhny Novgorod : Scientific Publishing Center "21st Century", 2019. – P. 320–324. – EDN CDKISX.

7. Zenkov, A. C. Numerical methods : textbook / A. C. Zenkov. – Yekaterinburg : Ural University Publishing House, 2016. – 124 p. – ISBN 978-5-7996-1781-3.

8. Kalitkin, N. N. Numerical methods : textbook / N. N. Kalitkin. – Saint Petersburg : BHV-Petersburg, 2011. – 592 p. – ISBN 978-5-9775-0500-0.

9. Technical Regulations of the Customs Union “On the safety of railway rolling stock” (TR CU 001/2011). // Rosrtansnadzor : official website. – URL: https://rostransnadzor.gov.ru/stor-age/%D0%9C%D0%A2%D0%A3%20%D0%9F%D0%9E%20%D0%94%D0%A4%D0%9E/%D0%A2%D0%A0%20%D0%A2%D0%A1%20001_2011.pdf?ysclid=mpzey54jdw868875485 (date of access: 29.05.2026).

10. Order of the Ministry of Transport of the Russian Federation dated June 23, 2022 No. 250 “On approval of the Rules for the technical operation of railways of the Russian Federation” // Garant : information and legal support. – URL: https://base.gar-ant.ru/405042985 (date of access: 29.05.2026).