Nonlinear dynamic lateral responses of curved railway track associated with high-frequency squeal noises

In urban environment, curve squeal is a strongly tonal noise emitted from wheel/rail contact caused by the passage of the train in tight curve rail. Wheel/rail contact can cause a traveling source of sound and vibration, which constitutes high-pitch noise pollution inducing a considerable concern of rail asset owners, commuters and people living or working along the rail corridor. The sound and vibration can be expressed in various forms and spectra. The undesirable sound and vibration on curves are often called squeal noises. This type of noise is commonly emitted in tight curve rails and can be annoying to nearby residents due to its tonal nature and uncertain excitation mechanism. This paper studies the effect of curve radii on the possible occurrence of curve squeal, which is devoted to systems thinking the approach and dynamic assessment in resolving railway curve noise problems. Curve track models in three-dimensional space have been built using finite element package, STRAND7. The moving train loads are applied in order to simulate nonlinear dynamic responses of curve track associated with squeal noise. The simulations of railway tracks with different curve radii have been carried out to develop state-of-the-art understanding into lateral track dynamics. Parametric studies have been conducted to evaluate static and dynamic responses. The dynamic responses of the track are found to be sensitive to the change of curve radii. The resonance peak in the lateral direction is related to the agreement of corresponding natural frequency of rail and the vibration excitation frequency under an individual rolling velocity. The outcome of this study will help provide some key parametric insights into fundamental dynamics of track in the lateral direction and establish the development of the dynamic design of curve track.