The present paper deals with the vehicle's traction electric drive, consisting of several various electric power sources. One of the main requirements for such systems are the safety and sustainable operations, achieved largely the implementation of an uninterrupted supply of the vehicle's propulsion system with an electric power. One way of realization of the required level of operational sustainability is usage of Multi Power Source Traction Drive. This type of vehicle's propulsion systems is widely applied on the ships, trains, planes, heavy trucks. The most important impact on the sustainability of functioning of the ship's propulsion system have operational conditions, especially for the cargo ship, operating in Arctic region. This paper presents the application of the L-Z-transform method to assessing the important parameter of the vehicle's operational sustainability - availability of the multi-state (MSS) Multi Power Source Traction Drive, which includes Diesel-Generators and Gas-Turbine-Generators considering the impact of the real operating conditions. Straightforward Markov method applied to solve this problem will require building of a system's model with numerous numbers of states and solve a corresponding system of multiple differential equations. L-Z-transform method, drastically simplified the solution.
