Train Horn Research Articles

Audibility of train horns in passenger vehicles

Studies of accident rates associated with train horn bans indicate that motorists rely on horns to warn them of approaching trains. However, researchers have not yet established the levels of horn sounds necessary for detection at railroad crossings. The purpose of this study was to obtain baseline measures of the auditory component of the motorist's detection task. Horn sounds recorded in three test vehicles were presented to 20 normal-hearing listeners in quiet and in four types of vehicle interior noise: engine idling, ventilation fan off; engine idling, fan on; vehicle moving at 30 miles/hr (mph), fan off; and vehicle moving at 30 mph, fan on. Thresholds of the horn sounds were determined by an adaptive procedure. Mean thresholds were lowest in quiet (1.8-4.4 dBA) and highest for the 30-mph, fan-on condition (49.7-58.4 dBA). Mean horn thresholds for all 12 noise conditions were more than 10 dB below the overall level of the vehicle interior noise. Our data are compared with those of previous studies and their implications are discussed. Actual or potential applications of this research include the establishment of a lower limit of signal-to-noise ratios required for the detection of horn sounds at highway-rail crossings.

Railway noise levels, annoyance and countermeasures in Assiut, Egypt

Summary A field study of railway noise has been carried out in urban Assiut City, which is the largest city in Upper Egypt. The railway line is located in the middle of the city and splits it into two parts. The goals of the study were: (1) to carry out measurements of the railway noise levels and establish the extent to which the measured levels exceed the permissible levels; (2) to consider appropriate countermeasures for reducing railway noise in the city; (3) to examine people’s attitudes towards railway noise. The results of the measurements showed that the railway noise levels in Assiut are higher than those set by Egyptian noise standards and policy to protect public health and welfare in residential area. Day–night equivalent continuous A – weighted sound pressure levels (Ldn) of 80 dB and higher were recorded, while the maximum permissible level is 65 dB. The Experiments showed that: (i) a ban on using train horns decreased noise level by 17 dB; (ii) using a barrier decreased noise levels by 12.7 dB; (iii) reducing the speed of the trains from 100 to 30 k/h decreased the noise level by 10.1 dB; (iv) doubling the typical distance between track centerline and the nearest buildings from 50 to 100 m decreased noise level by 4.3 dB. The attitude survey showed that 51.3% of dwellers of Assiut heard railway noise. Sixty seven percent of the respondents who heard railway noise felt highly annoyed. By increasing the noise level, the percentage of respondents who felt highly annoyed is also increased.

Improving Road Safety and Residential Quality of Life

The automated wayside horn system is designed to replace the train horn as a means of alerting motorists to danger and thus enhancing safety at highway-rail grade crossings. Furthermore, the wayside horn directionality is such that the warning sound is broadcast over a smaller sector than the train horn, thereby reducing residential noise. This article examines the results of an evaluation comparing train horns with wayside horns in the village of Mundelein, Illinois, USA. The study derived from previous work in Gering, Nebraska, and Ames, Iowa.During the 3 months covering the 'before' (train horn) period and through to 'after' (wayside horn), more than 19 500 crossing gate closures were recorded on videotape at three crossings. Analysis showed motorist violation of level-crossing laws decreased 68%, from an average rate of 3.53 per 100 gate closings when train horns were in use to 1.12 per 100 with the wayside horn. The decrease was statistically significant. Of equal importance was the decrease in residential noise. Sound measurements taken in a sample of residential yards showed a decrease in sound levels by more than 10 decibels (dB) at most locations. When plotted as sound contours, decreases in the area of coverage ranged from 85% at the 90dB level to 65% at the 70dB level.However, there are two issues with the use of wayside horns that need to be resolved. First, and most important, is that the wayside horn starts sounding when the warning lights begin to flash. This startles motorists, and some stop on the rail tracks. A second issue is the frequent unwarranted activation of the system, which encourages people to ignore the gate.

A reduced-scale railway noise barrier's insertion loss and absorption coefficients: comparison of field measurements and predictions

In situ testing determined the insertion loss ( IL) and absorption coefficients of a candidate absorptive noise barrier (soundwall) to abate railway noise for residents of Anaheim, CA. A 4000 m barrier is proposed south of the tracks, but residential areas to the north have expressed concerns that barrier reflections will increase their noise exposure. To address these concerns, a 3.66 m high by 14.6 m long demonstration barrier was built in the parking lot of Edison Field, Anaheim, as part of a public open house, thereby allowing for acoustical measurements. Insertion loss ( IL) was measured in third-octave bands assuming 1/2-scale construction. The IL for three, scaled railway noise sub-sources (rail/wheel interface, locomotive, and train horn) was measured at six, scaled distances. The highest total, A-weighted IL, after corrections for finite-barrier and point-source speaker effects was 22 dB(A) for rail/wheel noise, 18 dB(A) for locomotive noise, and 20 dB(A) for train horn noise. These results can be compared favourably to IL predictions made using algorithms from the US Federal Rail Administration (FRA) noise assessment guidelines. For the actual barrier installation, shielded residential receivers located south of the project are expected to see their future noise exposures reduced from an unmitigated 78 CNEL to 65 CNEL. Absorption coefficients were measured using time delay spectrometry. At lower frequencies, measured absorption coefficients were notably less than the reverberation room results advertised in the manufacturer's literature, but generally conformed with impedance tube results. At higher frequencies the correspondence between measured absorption coefficients and reverberation room results was much improved. For the actual barrier installation, unshielded residential receivers to the north are expected to experience noise exposure increases of less than 1 dB(A). This factor of increase is consistent with a finding of no impact when assessed using FRA guidelines for allowable increases of noise exposure.

Masked Thresholds and Predicting the Audibility of Auditory Displays: An Example for Long-Haul Trucks

Noise is an unfortunate by-product of our modern industrial society, with effects ranging from minor annoyance, to major risk of hearing damage, to inability to hear warnings and other signals. This paper presents an extensive observational study of the methodology aimed at predicting the audibility of auditory displays and warnings. While the details of the discussion relate specifically to long-haul truck-cab environments, the procedures are generally applicable to any instance where it is necessary for an individual to hear intentional or incidental sounds. The discussion includes spectral measurements of both the background noise and signals, calculation of masked threshold per ISO 7731:1986(E), and analytical comparison of signal spectra to masked thresholds to determine signal audibility. A specific example calculating the audibility of train horns in the truck cab environment is then presented. Recommendations for improving the audibility of signals in noisy environments are also provided.

Field measurements of a reduced-scale noise barrier’s insertion loss and absorption coefficients

In situ testing determined the insertion loss (IL) and absorption coefficients of a candidate absorptive barrier material as part of a project to abate railway noise in Anaheim, California. A 13<th>000-ft barrier is proposed south of the tracks, but residents of Yorba Linda to the north have had concerns that barrier reflections will increase their noise exposure. To address this issue, a 12-ft-high by 48-ft-long demonstration barrier was built in the parking lot of Edison Field, Anaheim, as part of a public open hours, thereby allowing for acoustical measurements. The barrier’s insertion loss (IL) was measured in one-third-octave bands assuming 1/2-scale construction. The IL for three (scaled) railway noise sub-sources (rail/wheel interface, locomotive, and train horn) was measured at six (scaled) distances. The highest total A-weighted IL, after corrections for finite barrier and point-source speaker effects, was 22 dB(A) for rail/wheel noise and 18 dB(A) for locomotive noise. Absorption coefficients were measured using a time-delay spectrometry technique, and were found to be much less than the reverberation room results advertised in the manufacturer’s literature, though the resulting increase for noise exposure to Yorba Linda residents is still expected to be less than 1 dB(A).

Automated-Horn Warning System for Highway-Railroad Grade Crossings: Evaluation at Three Crossings in Ames, Iowa

Traditionally, locomotive engineers begin sounding the train horn approximately one-quarter mile from the crossing to warn motorists and pedestrians approaching the intersection. To be heard over this distance, the train horn must be very loud. This combination of loud horns and the length along the tracks that the horn is sounded creates a large area adversely impacted by the horn noise. In urban areas, this area likely includes many nearby residents. The automated-horn system provides a similar audible warning to motorists and pedestrians by using two stationary horns mounted at the crossing. Each horn directs its sound toward the approaching roadway. The horn system is activated using the same track–signal circuitry as the gate arms and bells located at the crossing. Once the horn is activated, a strobe light begins flashing to inform the locomotive engineer that the horn is working. Horn volume data collected near the crossings clearly demonstrate the significant reduction of land area negatively impacted by using the automated horns. Residents overwhelmingly accepted the automated-horn systems and noted a significant improvement in their quality of life. Motorists preferred the automated-horn systems, and locomotive engineers rated these crossings slightly safer compared with the same crossings in the before (train horn) condition.

Oh! Say, Can You Hear that Train Coming to the Crossing?

How effective is the horn on trains in alerting motorists, cyclists and pedestrians of the approach of a train to a highway-railroad crossing? Road users become aware of trains approaching crossings either by seeing them, hearing the warning horn or by warning devices at the crossing. Auditory warnings have some advantages over others, but practical problems of sound transmission and the noise environment of road users limit their effectiveness. Factors that affect the audibility of train horns and crossing bells are discussed. Train and crossing bells are generally effective for persons in their immediate environment, but are relatively ineffective for occupants of closed vehicles. Because of the lack of reliability of the detectability of auditory warning signals provided to motorists and others approaching rail-highway crossings, they should visually scan the tracks to ascertain the presence of a train.

The Pennsylvania "Stop, Look and Listen" Rule

Concerns a case where a horse and buggy driver crossed a series of railroad tracks and was killed by a train. The buggy drivers vision was blocked by box-cars and the train driver did not sound the train's horn.