Drive train of a mobile machine

A drive train of a vehicle, comprising:

• a drive motor comprising an internal combustion engine;
• a traction drive driven by the drive motor, the traction drive having a primary unit driven by the drive motor;
• and
• a hydraulic work system driven by the drive motor, wherein the hydraulic work system includes at least one hydraulic pump driven by the drive motor, and wherein during braking operation of the vehicle, the hydraulic pump of the hydraulic work system delivers into a hydraulic pressure accumulator for energy recovery,
• wherein to deliver torque into the drive train and/or to absorb torque from the drive train the drive train includes an additional hydraulic machine unit which can be selectively placed in communication with the hydraulic pressure accumulator or a tank and is in the form of at least one hydraulic machine which is operable as a pump and a motor in the same direction of rotation, wherein the hydraulic machine has an inlet connection and an outlet connection and a switching valve device is provided to control connection of the inlet connection and the outlet connection with the pressure accumulator or the tank, and
• wherein a charge/discharge valve is in selective communication with the pressure accumulator and the switching valve.