The low-noise potential of low-vibration track

Poster (konferens), 2021

High-speed railway lines worldwide are increasingly built using slab-track technology, in which a reinforced concrete slab replaces the supporting function of traditional ballast and sleepers. The increased use, no longer limited to tunnels and bridges, is partly due to their lower maintenance, compact construction, and potential for effective isolation against ground-borne vibrations. However, rolling noise on slab tracks typically shows higher levels of noise radiation compared to ballasted tracks. There is an apparent conflict between ground-borne vibration and noise: The stiffness of the rail support determines if the vibrational energy is transmitted into the ground, exciting ground-borne vibrations, or stays in the rail, leading to higher noise radiation. In this work, a slab track construction type called low-vibration track is adapted such that both low vibrations and low noise radiation can be achieved without compromising. This is made possible by tuning the inertia of this system's booted sleeper and its surrounding elasticity to provide a low support stiffness at low frequencies and a high stiffness in the range where the rail has a high radiation efficiency. It is found that the track decay rate, an indicator for the radiated noise from the rail, can be increased significantly above 300 Hz.