Abstract: A system for detecting one or more vehicles, such as a train, on a rail track, includes at least one optical conductor extending near and parallel to the rail track with a light source and light detector coupled thereto. One or more sensors are coupled to the rail track and include the light conductor, which sensors affect the light attenuation in the light conductor locally upon the presence of the vehicle. The sensor includes a free elongated element, which is connected to the mass of the sensor housing via an elastic hinge connection. One end of the element lies against the light conductor running through the sensor housing, which one end subjects the conductor to a microbending in dependence on displacement of the rail.