| 摘要 |
The track (20A) has an acoustic complex (10) attached to the underside of its contact surface (1) and comprising a layer of a viscoelastic material (2) and a layer of mineral wool (3) with fixings (4) to hold it in place. The viscoelastic material has a surface density of 3 - 10 kg/sqcm, and preferably 8 kg/sq m, and is made from self-adhesive supple panels or bitumen paint. The mineral wool layer is 20 - 70 mm, and preferably 40 - 60 mm thick, and there is a metal structure (5) beneath it. A variant of the acoustic complex can include a sealed supporting layer of glass fabric or cork 15 - 25 mm thick between the bitumen paint and mineral wool layers.
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