Over the last years great efforts were directed to the numerical description of the sliding behavior of rubber blocks on various surfaces by means of the Finite Element (FE) Method. Two major mechanisms of the load transfer of traction forces can be observed depending on the characteristics of the sliding surface. On "soft" surfaces, i.e., snow surfaces, the penetration of the sliding surface by rubber blocks results in a resistance against sliding motion. This resistance permits in addition to the frictional process the transfer of traction forces. Such a mechanism may be viewed as an "edge effect". On "hard" surfaces a frictional mechanism is responsible for the transfer of the traction forces. In this paper details of different effects of both mechanisms are explained. For both of them appropriate numerical models were established.