Sources and mechanisms of wheel/rail noise: state-of-the-art and recent research

A review is presented of wheel/rail research studies, published since 1978. Additionally a study is presented which is focussed on the magnitudes and relative importance of vertical and horizontal forces in the wheel/rail contact zone. In the specific case and the frequency range 50–2000 Hz the vertical force appeared to be 3–10 times larger than the lateral (axial) force. Nevertheless radiation due to axial excitation of the wheel dominates the wayside sound pressure level in several one-third octave frequency bands. Another significant contribution to the wayside A-weighted sound pressure level is attributed to vertical excitation of the rail.