**1. Introduction**

Effective functioning of railway transport in the Republic of Uzbekistan plays a significant role in creating conditions for modernization, transition to an innovative path of development and sustainable growth of the national economy of the country [1, 2]. By their geographical location, the railways of Uzbekistan are an integral part of the Eurasian Railway Network and are also the largest transport and logistics facility of national importance [3]. Throughout the existence and functioning of railway transport works in close relationship with other sectors of the national economy of the Republic of Uzbekistan. One of its main tasks is to meet the needs of the economy by providing timely cargo and passenger transportation. The work in this direction is carried out in various aspects and is aimed at ensuring the safe maximum possible throughput and carrying capacity of the railway network of the Republic of Uzbekistan [4, 5].

The location and peculiarity of the climate of the Republic of Uzbekistan – aridity, a large amount of solar heat, continentality contribute to the mass cultivation of fruit and vegetable products and allow sufficiently high yields of fruits, berries and vegetable products, to provide not only domestic needs but also to supply products to the markets of the near and far abroad [6–12].

For the export of fruits and vegetables, a sufficiently large number of vehicles equipped with thermal insulation and refrigeration and heating installations are needed. However, at present, the fleet of refrigerated rolling stock, as well as the entire fleet of freight wagons of the railways of Uzbekistan, is experiencing a shortage of serviceable vehicles [4, 13–21]. The current state of the fleet of refrigerated rolling stock does not allow to supply of a large number of perishable goods to other countries, which negatively affects the development of perishable traffic in the Republic of Uzbekistan.

The thermal engineering properties of the thermal insulation material play an essential role in the design of the thermal fencing of the bodies of refrigerated vehicles [21, 22]. Various materials are used for the thermal insulation of wagons and containers: mineral wool, foams and polyurethanes, characterized by low values of thermal conductivity coefficients [14, 18, 20, 23, 24]. However, due to the presence of thermal bridges, moisture and deterioration of thermal insulation properties during operation in refrigerated wagons and containers, the thickness of body fences (walls, roof and floor) usually exceeds 160–200 mm and reaches 250 mm, which leads to a decrease in the internal useful volume of the body and an increase in the weight of the container. The reason for this is the imperfection of technical solutions for the construction of body fencing structures and thermal insulation materials. During operation, the insulation of the body fence ages and wears out due to the effects of vibration, temperature and humidity changes. Deterioration of the insulation quality of fences leads to fuel overspending and an increase in financial costs, and the volume of work increases with planned types of repairs.

At the same time, new materials are being used in related branches of technology [22, 25, 26], having the lowest coefficient of thermal conductivity and greater strength, which makes it possible to create solid bearing structures of smaller size and weight. Therefore, the development of new technical solutions and the search for promising thermal insulation materials for fencing bodies of refrigerated wagons and containers are relevant. In this regard, the main purpose of this research is to select areas of development and develop scientifically sound technical solutions to improve the thermal parameters of the bodies of refrigerated wagons and containers for the transportation of perishable goods in the conditions of the Republic of Uzbekistan.
