The wheel flat detector (WFD) uses sensors mounted into the rail webb to
measure the propagation of the shock wave in the rail, generated by the dynamic force acting on the rail from a wheel flat.
The signals from the sensors are processed in real time so
that the data of the vehicle passage are available after a few
seconds.
By compensate the measured shock wave for the attenuation in
the rail, the number of sensors can be reduced, and the
accuracy and MTBF will also be improved.