For forest machines (skidders, forwarders), due to the peculiarities of work cycles and a wide range of changes in resistance to movement, a power plant with a heat engine most of the time operates in a non-optimal mode. It is proposed to overcome this disadvantage by using an active trailer link. The issues of the features of the use of active trailers as part of road trains of forest machines are considered. A trailer with a variable base was chosen as the basis, as the most popular and widespread in the forestry complex. The structure of an electromechanical transmission based on the principle of using a central electric motor and a controlled interwheel power distribution mechanism is proposed. The principles of determining the power of thermal and electric motors are considered. A method for calculating the external parameters characterizing the power distribution mechanism based on the principle of matching the radii of the kinematic and power turn is proposed, and a design scheme for turning the road train is given. The main assumptions are formulated to justify the possibility of the proposed calculated dependencies. The way of synthesis of kinematic schemes of such mechanisms, approaches to design and production are indicated. A technology for controlling such mechanisms is proposed. An example is considered, a variant of the kinematic scheme of the power distribution mechanism is given. The ways of project realization are shown.