The article deals with the issues of choosing a redundancy method and the frequency of replacing tractor elements while ensuring the level of operational reliability in agricultural enterprises. It is noted that the operability of the system is ensured as long as there are reserve elements available to replace the failed main elements (and there is a possibility of switching the reserve elements into an operational state). One of the general methods for solving this problem is a method based on the use of Markov processes. In this case, the process of changing the states of the tractor is presented as a dynamic system, the state of which changes discretely in continuous time in a random manner.