The electric energy is generated by a fuel cell cluster or a diesel electric power pack. The modular energy storage concept is based on a lithium-ion battery system, an electric double-layer capacitor module and a flywheel. Furthermore, fast charging at wayside charging stations can be demonstrated. This configuration of the energy storage devices in combination with an intelligent and predictive energy management system permits a full electric operation mode. Thus, an emission-free operation of up to 2 km is possible.