A monitoring system for rail-borne transportation of goods or people in at least one car. The one or more cars may, for example, be railway cars or tram cars which are moved in the public rail system. The monitoring system according to the invention first of all includes a generator mount, which is integrated in at least one wheel bearing of the car. The generator mount is therefore used on the one hand as the bearing for a wheel of the car, and on the other hand to produce electrical energy, as a result of which it forms a power supply unit. The components which are required to produce the electrical voltage in the generator mount are integrated in the mount. One of these components is formed by a conductor arrangement which is used for induction of an electrical voltage to be generated. The monitoring system according to the invention furthermore includes sensor electronics, which are electrically connected to the conductor arrangement, for determining measurement variables which act on the conductor arrangement. As a result, the generator mount furthermore forms a sensor.