NOISE CONSIDERATIONS ON A A HIGH-SPEED RAILWAY IN JAPAN
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Studies of noise and vibration "pollution" caused by high-speed trains operating near residential areas are reported and means for their abatement are considered. Along the new Tokaido Line, the area where train noise now exceeds 85 dbA at 25 m from the track centerline extends over 200 km along the line, and for over 20 km train noise reaches 90 to 100 dbA. The noise mainly originates in wheels, rails, vibration of the rolling stock and vibration of the roadbed. Driving gears and current collectors pose no problem. The effects of noise on those dwelling along the line are two: emotional (annoyance, discomfort), and environmental (interference with such activities as conversation, telephoning, watching TV, reading, study, rest and sleep). These effects have been confirmed by a questionnaire-type survey of the community response of those living within 200 m of the tracks. Japanese highway-environment noise standards specifying a 60 to 65 dbA peak noise level is found by this survey to be what the rail-side community also seem to require. Proposed noise-abatement measures include: car-body weight reduction; maintenance of smooth wheels and rails (otherwise a 5 to 15 dbA noise increase can occur); vibration isolators between rails and roadbed; "low-hemline" shielding on cars; a noise baffle along the trackside; a 50 m buffer zone along the railway; a noise insulation wall between residence and tracks.