The timeframe for evacuating the wounded is a critical factor that largely determines the fate of a wounded soldier. Even at the initial stage of the war waged by the russian federation against Ukraine, there were almost no frontline ambulances, and there was a critical shortage of ambulances. At present, despite significant efforts to provide the Armed Forces of Ukraine with weapons and military equipment, as well as material and technical means, including medical equipment and property, in particular through international technical assistance, the problem of the lack of the required number of specialised medical evacuation vehicles has not been fully resolved. From this point of view, the issue of correct formulation of requirements for the rational composition and specially equipped various types of vehicles (including sanitary transporters, ambulances), including general use, the system of evacuation of the wounded, and determining the possibility of its further improvement through the methodological apparatus is relevant. The purpose of the article is to present a methodological approach to determining the main parameters of the system of evacuation of the wounded of an operational group of troops with the involvement of various types of transport. The formation of a model of the casualty evacuation system as a mass service network (MSN) will minimise the time spent waiting for medical care by wounded personnel, determine the rational composition of forces and means of the tactical casualty evacuation system. To model the system and processes of evacuation of the wounded from the battlefield during hostilities, including their transportation to medical facilities located in the depths of the third logistics zone, the mathematical apparatus of the theory of mass service was used. In particular, we are talking about the devices of queuing systems (QS) and MSN. The existing system of military evacuation of the wounded and sick is a four-tier system in which all wounded with moderate and severe severity are evacuated. Based on this, the system of evacuation of the wounded can be represented as an MSN, which has a number of features. First of all, this MSN is an open queuing network (OQN), i.e. the flow of requests to enter the network is unlimited, homogeneous and comes from an external independent source. As a result of the calculations, data were obtained on the values of network parameters (average number of applications in queues – 119.47 applications/hour, average number of applications in the network – 158.53 applications/hour, average waiting time for applications in queues for service – 11.95 hours, average time of application stay in the network – 15.85 hours) and the parameters of each QS operating in the MSN – transmission coefficient, incoming flow intensity, load factor, average number of busy channels, average number of applications per QS, average queue length, average waiting time for an application in the service queue, average time for an application to stay in the QS. Analysing the calculated data, from the point of view of creating a rational OQN, the casualty evacuation system achieves maximum efficiency when its productivity in processing the incoming flow of requests is maximised, and the minimum values of such parameters as the number of requests for service in the queue and the number of service channels operating in the network are minimal.
