By Stephan Marsar
Ever wonder why the train locomotives running on the track just down the block always sound their air horns four times when approaching the crossing? Or, ever hear a whole series of short and long train whistle blasts and wonder what they mean? Train horns are sounded for safety reasons – to warn of the approach of a moving train.
A Proven Safety Precaution
Prior to radio communications, which came about in the 1960s, train whistles and horns were the only way for the engineer to convey information to other employees, both on and off the train, on the impending train’s movement. On April 27, 2005, the Federal Railroad Administration (FRA), which enforces rail safety regulations in the United States, published the Final Rule on Use of Locomotive Horns at Highway-Rail Grade Crossings. Effective June 24, 2005, the final rule requires that locomotive horns be sounded at all public grade crossings 15 to 20 seconds before the locomotive enters the crossing but not more than ¼ mile in advance of such grade crossing.
The established pattern for blowing train horns is two long, one short, and one long sounding to be repeated as necessary until the locomotive clears the crossing. Locomotive engineers retain the authority to vary this pattern as necessary for crossings in close proximity to residential neighborhoods and will be allowed to sound the horn in emergency situations.
Train Whistle, Shmain Whistle
A ban on locomotive horns at grade crossings in the state of Florida was removed by the FRA after it was shown that the accident rate of trains striking vehicles more than doubled during the ban’s relatively short tenure (1984-1989). The final rule by the FRA preempts all state or local laws regarding the use of train horns at public crossings. The rule does provide public authorities the option to maintain and/or establish “Quiet Zones” provided certain supplemental or alternative safety measures are in place (gates, audible signals for vehicles and pedestrians, etc.) and the crossing’s accident rate meets FRA standards (they have acceptable standards for grade-crossing accidents? Geez!).
Who Knows of These Air Horn Devices?
Although federal, state, and local standards, laws, and rules regarding lights and sirens lack uniformity, there have been many statistical analyses and studies done on their use (and abuse). Those studies all indicate that sirens are low-speed devices.1 Sirens are most effective between 10 and 30 miles per hour (mph) and become less effective for every five mph above those speeds.2
Data (and experience) clearly show that intersections pose the greatest collision risk and that emergency vehicles are more likely to be struck by another vehicle than vice versa.3,4,5 Therefore, the ability of another driver to detect and safely avoid an approaching emergency vehicle is crucial to preventing emergency vehicle crashes. Trains are required to sound their horns/whistles at all public grade crossings 15 to 20 seconds before the locomotive enters the crossing but not more than ¼ mile in advance of such grade crossing.
Emergency vehicle warning devices work best when they are sounded starting approximately 200 feet before the intersection and using alternating patterns between high and low frequencies (mechanical sirens) and between wail and yelp (on electronic sirens). It’s been found that the American “Hi-Lo” pattern (meant to replicate the pattern of air horns used on European emergency vehicles) is ineffective and the use of other sounds (electric air horn, phasor, etc.) is ineffective because the public doesn’t recognize them as sirens; they just (sometimes) hear the noise and instinctively start looking around.
Air horns are common additions to sirens on larger emergency vehicles. However, little has been written on these warning devices. Some suggest that the dual-trumpet air-powered horns are the best,6 but just Google “train horns on fire trucks” and you’ll see a hybrid and direct link between fire trucks and train horns. Some experts caution against drowning out the siren at crucial times when using a constant simultaneous air horn blast.7 The lack of published data on air horn effectiveness may keep us from drawing any firm conclusions on their effectiveness.8 However, any self-respecting firefighter and/or fire officer and/or apparatus driver will tell you that air horns usually get people’s attention much better than sirens do.
Whiskers on Kittens
With the above in mind, I started to experiment and listen to the use of air horns on fire apparatus, ambulances, and police car responses. I observed and tried different patterns of blasts and even applied the FRA’s two long, one short, and one long pattern to see if it would work. I invite you to do the same on your next response.
Here’s what my totally unscientific and haphazardly implemented experiment found (hearing test failure notwithstanding):
- The constant and steady blaring of the air horn absolutely drowns out the siren, regardless of type (mechanical, Q2, Q2B, electronic, electro-mechanical, whatever) and regardless of the pattern (wail, yelp, phasor, Hi-Lo, etc.). It also kills brain cells and ruins everyone’s hearing!
- The railroad’s pattern works, but I think it’s more about the change in pattern rather than the actual pattern itself.
- The most effective air horn pattern I found is an adaptation of the railroad’s: two long, two short, two long. Applied significantly prior to entering intersections (approximately 200 feet) and in conjunction with changing the siren’s pattern, it got people’s attention, allowed them to recognize we were coming, and gave them time to take evasive action.
- The use of phasor and Hi-Lo siren patterns is almost useless in getting people out of the way.
- The use of the electronic air horn button found on most electronic sirens is somewhat effective, but its use cuts out the siren – which is a major drawback. Coupled with the public not recognizing it as an emergency warning device, this makes their use questionable at best.
Note: All the previous observations are of course dependent on apparatus speed, weather conditions, ambient noise levels within vehicles and on the streets (radios, Bluetooth, sound-deadening vehicles, engine noise, construction, etc.), all of which reduce siren effectiveness.
Cats use their whiskers to gauge whether they will fit into a certain space. They use them to cautiously enter behind dressers, couches, or dead tree stumps before cautiously proceeding. Using a change in siren pattern, combined with selective (not just indiscriminate) air horn use, will allow us to cautiously enter intersections and drive on roadways for a safer, faster, and more efficient response.
(For a well done video on siren effectiveness, check out this one produced as a public service announcement from the Monmouth Ocean Hospital Service Corporation of New Jersey: http://www.monoc.org/newPub/sirenPSA2.cfm.)
Resources
1. Scarano, Steve, “The sights and sounds of emergency vehicles,” Emergency 1981, 13:38-41.
2. Staff report, “Exploring the intersection illusion,” Mechanical Engineering, February 1986, 37-39.
3. Auerbach, PS, JA Morris, and JB Phillips Jr, et al, “An analysis of ambulance accidents in Tennessee,” JAMA, 1987, 258:1487-1490.
4. Elling, Robert, “Dispelling myths on ambulance accidents,” JEMS, 1989, 14:60-64.
5. Newcomb, FD, and K Carpenter, “Emergency Vehicle Accident Involvement 1969-1970,” New York State Department of Motor Vehicles, 1972.
6. Lamm, WH, “Vehicle Warning systems,” Emergency, 1983, 15:32-35.
7. Skeiber, SC, RL Mason, and RC Potter, “Effectiveness of audible warning devices on emergency vehicles,” Sound Vibration, 1978, 12:14-17, 20-22.
8. Skeiber, SC, RL Mason, and RC Potter, “Effectiveness of Audible Devices on Emergency Vehicles,” US Department of Transportation, National Highway Traffic Safety Administration, publication No. DOT-TSC-OST-77-38, 1977.
Stephen Marsar, EFO, MA, is a 28-year veteran of the fire service and battalion chief in the Fire Department of New York (FDNY). He is also a former chief and commissioner of the Bellmore (NY) Volunteer Fire Department. Marsar teaches extensively at the FDNY and Nassau County (NY) Fire and EMS academies, and he’s an adjunct professor at the Nassau County Community College. He has a master’s degree in homeland defense and security from the U.S. Naval Postgraduate School as well as a bachelor’s degree in fire science and emergency services administration from SUNY Empire State College. Marsar graduated with honors from the National Fire Academy’s Executive Fire Officer Program and is a National Roll of Honor inductee.
