WhisperCabTM
In recent years, an
increased emphasis has been placed on enhancing crew comfort in the cab. The
introduction of the "Modified" or wide cab made major strides towards this
goal. Among the amenities with such a design comes noise reduction. A typical SD70M
locomotive generally creates approximately 85-87 dBA in the cab during a
throttle 8 load test. The same locomotive outfitted with a sound reduction package
generally drops noise level to approximately 83-85 dBA. Much of the
noise created in the cab results from structural vibrations. Since the diesel engine
and cab both mount to the locomotive's underframe, vibrations transmit into the walls
of the cab. So because of the cab's mounting, noise is difficult to suppress.
WhisperCabTM
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UP demonstrator 8075 on
CPR - Greg Sherwood.
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Recently, Electro-Motive unveiled its Isolated Cab design (now known
as WhisperCabTM). Rather than having the cab bolt
to the underframe, this design places the cab on rubber pads or "isolators".
Furthermore, with slip joints at the front and rear, the cab becomes a segregated
unit. Calculations show that the SD90MAC locomotives during a throttle 8 load test
will produce a sound level in the cab equivalent to or less than a
non-isolated M cab with a sound reduction package running at idle. This
represents a significant reduction in noise levels.
©
2005 William C. Slim
http://www.okthepk.ca
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