Optimizing Components in the Rail Support System for Dynamic Vibration Absorption and Pass-By Noise Reduction

The rail pad stiffness is central in the conflict of interest between reducing airborne noise or track loads. Slab tracks typically have a low rail pad stiffness. This study explores two-stage elastic rail supports for slab tracks as a means to reduce noise while not increasing the track loads and hence ground vibrations. In a time-domain simulation, track forces and noise radiation are compared for several setups with parametrized rail support components. The results show that (I) the rail pad stiffness is the major lever for adjusting the radiated sound power, (II) the lower stiffness is important for adjusting the rolling contact forces and load on the track components, and (III) that optimizing for a lower sound power generally produces higher rolling contact forces.