Abstract: A parallel hybrid drive train, in particular for a working machine, includes an internal combustion engine (1), an electrical machine (2) and hydraulic aggregates (3, 4, 5, 9) for driving working devices (6-8) and for moving the working machine. In order to increase the efficiency, the rotational speed of the internal combustion engine is lowered, that is to say the load point is moved. Increased power requirements are detected via a driver input and provide a desired rotational speed. The electrical machine assists the acceleration of the internal combustion engine to said desired rotational speed.