LOW NOISE TRACK MEETS ENVIRONMENTAL CONCERNS

This article describes various means of reducing the noise generated by railway track. For overall noise control, it is necessary to address also the need to reduce wheel-generated noise, as the most important mechanical noise source is the wheel/rail contact, producing vibrations. One way to cut noise is to reduce the roughness of both wheel and rail. Vibrations transmitted into the ground beneath the track can also propagate over significant distances. For track noise, the most successful noise reduction measure was a rail damper, where multiple blocks of steel are fixed to the rail by an elastomer. Other components include a low barrier next to the rail. Concrete slab tracks have become more common but are noisier than ballasted track. Noise can be reduced by adding absorbent material to the upper surface of the slab and shielding the rails by an integrated mini-barrier. For reducing ground-borne noise, it may be possible to design tracks with low resonance frequencies. One technique for introducing resilience is the use of ballast mats.