Authors: U.S. Department of Transportation, Federal Railroad Administration

Date of Publication:  1995

Sponsoring Agency:  U.S. Department of Transportation, Federal Railroad Administration

Report No:

Abstract:

The assessment of the potential noise impact of the proposed, Use of Locomotive Horns at Highway-Rail Grade Crossings rule, relies on criteria for noise impact developed by the Federal Railroad Administration (FRA).  The criteria are based on research conducted by the U.S. Environmental Protection Agency (EPA).  Impact at each current whistleban crossing was assessed by comparing the horn sounding environment to a quiet zone environment.  Severity of noise impact from horn sounding was rated according to the relative increase in noise levels.

A generalized horn sound model was developed by Harris Miller Miller and Hanson (HMMH) under subcontract to Parsons Transportation Group for FRA.  The model includes sound source levels based on measurements and previous studies, sound exposure calculations based on train speeds and the number of trains passing during day and night at each crossing, propagation of sound to nearby neighborhoods based on typical suburban terrain and building configurations, and community reaction estimation based on EPA and FRA noise research.  The computer model uses relevant data for each grade crossing under study, such as number of trains per day and night, speed, and number of tracks, drawn from the US DOT/AAR Grade Crossing Inventory.  The model then calculates noise impact areas at each location represented by five-sided polygons.  Two zones of noise impact are defined, impact, and severe impact as a subset of impact.  In the impact zone, the change in the sound level is expected to be noticeable to most people, but may not be sufficient to cause strong, adverse reactions from the community.  In the severe impact zone, a significant percentage of people are likely to be highly annoyed by horn sounding.

The estimated total population residing within the two impact zones at each current whistleban crossing represents a worst case measure of the potential annoyance from the proposed rule.  Impacted population at each crossing was estimated by Parsons Transportation Group using a geographic information system (GIS) by overlaying noise polygons with census block data.  Finally, the horn noise model was used to assess the effects of other provisions of the proposed rule on locomotive horns that would benefit all communities with public highway-rail grade crossings.  A typical crossing drawn from data on 147,653 crossings was modeled and the resulting population benefits estimated using 1990 census tract data.
 

No. of Pages:  83