Device for achieving a high spread of speeds with high efficiency in a drive train of a driven machine or installation, comprising (i) two power machines (A1, A2), working by means of motor or generator, which are connected in a rotationally fixed manner, either indirectly via suitable coupling elements, transmission members and/or translation devices (7, 8) or directly, to a carrier shaft and a slower of two stationary-gear shafts of an epicyclic gear train, where one of the power machines is coupled to the carrier shaft, and the other power machine is coupled to the stationary-gear shaft that is running more slowly in terms of absolute value; (ii) a work machine, which is connected in a rotationally fixed manner, either indirectly via coupling elements, transmission members and/or translation devices or directly, to the faster of two stationary-gear shafts of the epicyclic gear train, and (iii) the internal movements of the epicyclic gear train are blocked in one direction of rotation and allowed in the other direction of rotation, where (a) one or more of the coupling devices (6, 7, 8) is connected in a rotationally elastic manner to one or more of the transmission members involved, or (b) the speeds at the optimum points of the installed power machines with respect to efficiency are essentially the same or differ from one another by a maximum of 10%, or (c) the torques at the optimum points of the installed power machines with respect to efficiency are essentially equal to the absolute value of the reciprocal, reduced by 1, of the product of stationary translation and stationary efficiency in the power flow direction of the epicyclic gear train used, or differs from this ratio by a maximum of not more than 10%. (i) two power machines (A1, A2), working by means of motor or generator, which are connected in a rotationally fixed manner, either indirectly via suitable coupling elements, transmission members and/or translation devices (7, 8) or directly, to a carrier shaft and a slower of two stationary-gear shafts of an epicyclic gear train, where one of the power machines is coupled to the carrier shaft, and the other power machine is coupled to the stationary-gear shaft that is running more slowly in terms of absolute value; (ii) a work machine, which is connected in a rotationally fixed manner, either indirectly via coupling elements, transmission members and/or translation devices or directly, to the faster of two stationary-gear shafts of the epicyclic gear train, and (iii) the internal movements of the epicyclic gear train are blocked in one direction of rotation and allowed in the other direction of rotation, where (a) one or more of the coupling devices (6, 7, 8) is connected in a rotationally elastic manner to one or more of the transmission members involved, or (b) the speeds at the optimum points of the installed power machines with respect to efficiency are essentially the same or differ from one another by a maximum of 10%, or (c) the torques at the optimum points of the installed power machines with respect to efficiency are essentially equal to the absolute value of the reciprocal, reduced by 1, of the product of stationary translation and stationary efficiency in the power flow direction of the epicyclic gear train used, or differs from this ratio by a maximum of not more than 10%. (a) one or more of the coupling devices (6, 7, 8) is connected in a rotationally elastic manner to one or more of the transmission members involved, or (b) the speeds at the optimum points of the installed power machines with respect to efficiency are essentially the same or differ from one another by a maximum of 10%, or (c) the torques at the optimum points of the installed power machines with respect to efficiency are essentially equal to the absolute value of the reciprocal, reduced by 1, of the product of stationary translation and stationary efficiency in the power flow direction of the epicyclic gear train used, or differs from this ratio by a maximum of not more than 10%.