ACTIVE NOISE REDUCTION AND VIBRATION CONTROL IN LOCOMOTIVE CABS - ISSUES, IMPACTS, AND MOTIVATIONS FOR RAIL OPERATIONS WORLDWIDE

摘要

Active noise reduction and vibration control have been successfully applied in many settings to reduce low frequency noise or vibration. The benefits of active noise reduction or vibration control depend upon the acoustic content of the environment in which it is installed. Often an active control installation is considered successful based on the instantaneous impact. For low-frequency dominant environments, the benefits also include improved long-term comfort, health, and safety; the ability to better meet regulatory requirements; and a possible reduction in risk of litigation. Costs of active systems include the financial cost - but also the physical size and weight of the active equipment, the burden of installation and tuning, and other concerns. Even considering these costs, locomotive cabins represent a particularly compelling application for active control. This paper begins with an analysis of the noise and vibration content experienced by engineers in North American and European locomotive cabs. This analysis establishes clearly the low frequency and tonal dominance of the acoustic and vibration signatures found in locomotive work environments. In addition to comparisons with the noise and vibration experiences in other workplaces, the noise and vibration data will be compared against existing regulations and generally accepted physiological exposure limits and guides. Poorly executed government regulations and future global regulatory trends are also considered. Using both control simulations and actual active control installations, this paper then describes the specific costs and benefits of active control for locomotive cabins in detail. What the reader will see is that locomotive cabin noise reduction and vibration control represents an application of extremely high value to the owners of locomotive fleets and the personnel who drive them. This should lead to an early general acceptance of active noise reduction and vibration control in the locomotive market.