Rail Environmental Sustainability

Providing a Cleaner Alternative to Trucks

On average, trains are three to four times more fuel-efficient than trucks, moving one ton of freight 470 miles on one gallon of diesel fuel. Rail moves 40 percent of the nation’s freight tonnage while emitting only 0.6 percent of all greenhouse emissions and eight percent of all freight emissions. The American Association of Railroads estimates that shipping by rail instead of trucks reduces greenhouse gas by 75 percent. (Sources: Association of American Railroads. Freight Railroads Embrace Sustainability & Environmental Preservation. (February 2019). United States Department of Transportation (USDOT), Federal Rail Administration (FRA). (2018).)

Train Noise Pollution

Next to long delays at rail grade crossings, noise from train horns is a common complaint heard from communities located along the region’s rail corridors. Issues ranging from annoyance to sleep disturbance have been reported. The noise from train horns is not constant, however due to the high train volumes along many corridors, the great number of public rail grade crossings and the reality that freight trains operate around the clock — the frequency of train horns fluctuates hour to hour and day to day to impact the daily lives of residents and businesses.

The Federal Rail Administration (FRA) states that under the Train Horn Rule (49 CFR Part 222), train horns must be sounded at least 15 seconds, and no more than 20 seconds, in advance of all public rail grade crossings. If a train is traveling faster than 60 mph, the horn will not be sounded until the train is within quarter mile of a public rail grade crossing.

There is a standardized pattern for train horns of two long, one short and one long blasts. However, there are no rules for what defines a “long” and “short” horn signal. The pattern must be repeated until the lead train engine is within the rail grade crossing. The Train Horn Rule also requires that train horns must be between 96 and 110 decibels.

Due to the impact of train horn noise on the quality of life for citizens in the OKI region, staff wanted to estimate the level of impact upon our population. OKI used distances of a quarter mile and eighth of a mile from each public rail grade crossing to create noise polygons or contours similar to those used for airport runways.

The methodology OKI employed used a reference level that varied along the railroad beginning a quarter mile in advance of a crossing and ending at the crossing. Field measurement data showed an average reference sound exposure level (SEL) of 107 dBA at 100 feet from the nearest track which represented the horn noise in the distance from one-fourth mile to one-eighth mile from a crossing. The SEL represents the duration and the magnitude of a time-varying noise event such as the sounding of a train horn. SEL measures how loud the noise is and how long the noise lasts. Starting at the one-eighth mile distance, the data showed the horn is sounded more continuously and more loudly in the last part of the blowing sequence as the train reaches the crossing.

OKI further buffered all train tracks by 100 feet for train noise other than a train horn and each at-grade crossing was given three levels of noise buffering. The first buffer (800 feet) began along the train track from a quarter mile away extending to an eighth of a mile, the second (1000 feet) extended from the eighth mile to the crossing and finally a 1100 feet buffer was drawn around crossing.

The results of this analysis have been included in a new OKI interactive rail mapping tool. Within the map, the train noise impact areas are shown. Demographic data for the train noise impact areas was used to find that 111,235 people, about five percent of the region’s population, or 50,226 housing units are impacted by train horn noise.

To view the most current train noise data, visit OKI’s Interactive Rail Map.