A novel approach for the measurement of absolute train speed

This paper presents a new approach for the measurement of the absolute travelling speed of rail vehicles. Unlike the conventional techniques where the vehicle speed is obtained from the measurement of rotational speed of wheelset axles, the proposed method derives the speed indirectly from the time shift between motions of any two wheelsets. It will explore vehicle/bogie dynamic responses to track excitations, and extract particular features of motion at the wheelsets from inertial sensors mounted on the bogie frame. The new technique will be able to provide an accurate measurement of the vehicle ground speed, even when the wheel slip/slide occurs under traction/braking. The performance assessment of the proposed measurement method using a conventional bogie vehicle is provided, including the robustness against the parameter variations in the suspensions and the reduced level of track roughness at low travelling speeds