Train location with eddy current sensors

A robust train location system with a novel eddy current sensor is proposed. The new system is purely train-based in the sense that no further installations are required on the track beyond the currently existing infrastructure. The eddy current sensor system consists of two identical sensors placed at a distance 1 in longitudinal direction. Thus, the time delay between the two sensor signals obtained by cross-correlation is a measure for the velocity of the vehicle. In addition, the sensor signals are analysed for characteristical events. The shape of the sensor signals highly depends on the irregularities of the magnetic properties of the rail arising along the track. In particular, it is shown that the characteristic signals of the components in switch areas differ significantly from the signals caused by rail joints along the straight track. This knowledge can be exploited for detection and classification of switches and switch components. Matching the measured position of points with topological position data from a digital route map yields reliable location of the train.