Contemporary trends show a marked tendency for solution of problems of dynamic analysis of drive systems as early as the design stage. It shows that during the modelling of complex drive systems it is necessary to respect its structural complexity and therefore it is necessary to make the models of particular drive subsystems first and then to combine it altogether. In the paper authors present some methods of creation of suitable mathematical models of complex drive systems respecting the drive structure. The methods are then applied onto real tasks. Examples are included.