Personal and area noise dosimetry measurements were taken in the cabs of leading and trailing locomotives on 48 trips, under winter and summer conditions, on 9 different routes. The mean equivalent sound level (L ind(EQ) 3 dB exchange rate, 50 dBA threshold) of the engineers and conductors was 84 dBA during winter and 88 dBA during summer. The corresponding time- weighted average levels (LTWA, 5 dB exchange rate, 80 dBA threshold) were 80 and 84 dBA respectively. The LEQ of 56% of the engineers sampled was >/=85 dBA and of 13% was >/=90 dBA. Plots of L EQ time history show that under normal operating conditions Lgo reaches its steady-state value in about 3 hours. The mean noise levels in the trailing cabs were lower than the personal exposure levels of the engineers and conductors. The mean L EQ on the engineer and conductor sides was 80 dBA during winter, and 85 dBA during summer. Locomotive configuration has a significant effect on the noise levels in the trailing cab. The forward- backward configuration resulted in higher noise levels than the forward-forward configuration. Octave and one-third octave band spectra taken during a variety of locomotive operating conditions are presented. The octave band centered at 31.5 Hz contains nearly 46% of the acoustical energy, and those centered at and below 250 Hz contain nearly 99% of the acoustical energy Wheel-rail interaction appears to be the predominant source of the low frequency noise. Recommendations for controlling exposure are made.
Exposure to noise on board locomotives
AIHA Journal ; 64 , 5 ; 699-707
2003
9 Seiten, 6 Bilder, 3 Tabellen, 17 Quellen
Aufsatz (Zeitschrift)
Englisch
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