Typically, the wagons of a freight train do not have an electric train supply (ETS), which is in contrast to passenger coaches, where such a supply is used for coach lighting and heating. An emerging application, which, however, requires an electric power supply, is condition monitoring of freight wagons, e.g. an anti-lock braking system, or of the transported goods. It has the potential of saving costs and giving additional benefit to the freight wagon's operator. Therefore, systems suitable for providing auxiliary electric power in the watt-range on a freight wagon are analyzed in this thesis. State-of-the-art auxiliary energy generation systems as, e.g., axle generators on freight wagons lack the possibility of a cost-effective retrofit. Therefore, energy harvesting (EH), which can, according to the literature, generate power from temperature gradients, radiation, mass flow, and vibration is analyzed further as it is expected to be a more acceptable approach. However, power ratings of such systems typically range from a few microwatts to milliwatts. In order to increase the power supply capability, providing auxiliary power on a freight wagon with EH from kinetic energy is pursued further. Harvesting electric energy from the kinetic energy of a moving conductive surface (MCS) is analyzed as a high power delivering capability of such system is expected. Specifications for the system can be summarized as follows: MCS of steel, similar in composition to a typical freight wagon's wheel, wheel speed of v_2=80km/h, harvesting contactless over an air gap of 10mm, and finally providing an electrical output power of P>5W. As no severe modifications (as e.g. mounting permanent magnets) on the MCS are allowed, the only feasible option is to extract power electrodynamically. Hence, an EH system is building up a magnetic field, which excites eddy currents in the MCS. Similar to the operation of an induction machine, eddy currents and the magnetic field build up Lorentz forces, which establish an electromechanical energy conversion/transfer. Initially, a single-sided linear induction machine (SLIM) in generator operation mode is considered for this task. An output power scaling law is derived and a prototype test setup is built. The power scaling law, together with an experimental verification shows that EH/energy generation with a stator of reasonable size (covering 47cm^2 of MCS surface) is only possible for low air gap widths (