Abstract: A drive train, wherein the drive train has a first electric machine (EMI) which can be operated in a motor or generator operating state, and a planetary gear mechanism (100) having a rotational-speed changing apparatus, wherein the rotational-speed changing apparatus is configured, in particular, as an internal gear (110) and/or as a planetary gear (114) and/or as a sun gear (112), wherein the planetary gear mechanism (100) has a drive side and a driven side, characterized in that the first electric machine (EMI) engages into the rotational-speed changing apparatus in a controlling manner in the motor or generator operating state, with the result that a step-up transmission ratio is formed in the planetary gear mechanism (100).