What’s the Right Air or Train Horn for Your Truck?

Horns date back to the locomotive steam days and were used as a precautionary measure to warn the public and railroad employees while in motion. Today, they are used on a wide variety of vehicles and trucks outside of the rails. Here’s everything you need to know about them and the best ones for your truck.

What is a Train Horn?

This powerful air horn serves as an audible cautioning device on diesel and electric locomotives. Its main purpose is to notify persons and animals of an oncoming train especially when arriving a grade crossing, and it is also used to avow signals given by railroad employees when switching operations.

History and Background of Train Horns

Due to the enormous weight and inertia weight of a train, it was difficult for trains to quickly stop when faced with an obstacle. These trains moved on fixed rails, making them prone to collusion, so from the onset, locomotives have had loud horns specifically to warn vehicles and pedestrians of its approach and also acknowledge signals given by railroad employees.

Steam locomotives had steam whistles while diesel locomotives used air horns since they were not compatible the more common steam whistles. The air horn design was then upgraded and modified for railroad use thanks to their much higher musical note. Strict regulations are specific to each country specifying how loud the horn must be. Standard signals consisting of diverse sequences of horn blasts must be given in different circumstances.

How Train Horns Work

Train horns work by producing compressed air, commonly 125-140 psi, fed from a locomotives main air reservoir. When the horn valve is opened, air flows through a contracted opening between a nozzle and a circular diaphragm in the power chamber, then out via the flaring horn bell.

The passage of air past the diaphragm causes it to oscillate against the nozzle, thereby producing sound. When vibrated by the diaphragm, the column of air in the bell vacillates with standing waves. The length of the bell determines the wavelength of the sound waves, and pitch of the note produced by the horn which is measured in Hertz.

What is an Air Horn?

This pneumatic device was designed to create an excessive loud noise for signaling purposes. It usually consists of a source which produces compressed air, which passes into the horn via the diaphragm. The steam of air causes the diaphragm(reed) to oscillate, thereby producing sound waves. The sound is then amplified by the horn, making it louder. Horns are generally employed as vehicle horns and are installed on large semi-trailer trucks, trains, fire trucks, on some ambulances as a warning device and on ships as a signaling device.

How Does an Air Horn Work?

An air horn consists of a flaring metal or plastic horn or trumpets called the bell which is usually attached to a tiny air chamber containing a metal diaphragm in the throat of the horn. Compressed air flows from an inlet line via a narrow opening past the reed, making it vibrate, thereby creating sound waves. The flaring horn determines the pitch of the sound when vibrated by the reed, the column of air in the horn vibrates in standing waves and it also serves as an acoustic transformer that improves the transfer of sound energy from the reed to the open air, making it sound louder.

The length of the horn determines the wavelength of the sound waves produced and thus, the pitch of the note is generated by the horn. The longer the horn, the longer the pitch. Bigger air horns are used by ships and forghons and they perform similarly to a whistle. In this case, instead of the reed, the air escapes from a closed cylindrical resonator chamber via an exact shaped slit directed against a flipple. The air blowing past the flipple vacillates, creating sound waves. The vacillation excites standing waves in the resonator chamber, so the length of the chamber ascertains the pitch of the note generated.

How Does an Air or Train Horn Work on a Truck?

In trucks, the air horn is self powered with compressed air from the vehicle’s air brake system. A cord is mounted on the ceiling of the operators cab which is pulled to open the valve, thereby supplying various amounts of air to the horn. In modern trucks, the horn is triggered by pressing a button on the steering wheel. Some trucks also have both the electric horn and the air horn which is select able by a switch on the dashboard and this is used to prevent the use of powerful air horns in populated areas. Another popular setup using a mounted tank of compressed air can be seen in the below diagram.

What is the Main Difference Between Air Horns and Train Horns?

Larger train horns tend to be louder and sounds deeper than smaller air horns. The smaller air horns have narrower trumpets, so they produce a higher pitch than that of a larger train horn.

Where Can You Get High Quality Horn Kits?

For over 16 years, HornBlasters has designed and sold top of the line horn sets and kits. Since inception, they have focused on building the highest quality, best-performing, and most satisfying products available. As an industry leader of horn kits, they are proud to use their years of experience, research and development to bring new solutions to consumers without breaking the bank.

Why Are HornBlasters Products The Best On The Market?

  • HornBlasters train horns are of the finest quality.
  • The tuning of our horns is musically accurate. Each horn is adjusted in pitch to a specific note and is accurate to 1Hz. Together, our horn kits play easily recognizable and authentic locomotive chords.
  • All HornBlasters kits feature DOT/SAE JID/ASME spec air line and fittings.
  • We do not use any generic spare parts in our kits, everything used is both of the highest quality and hand selected to be used in our kit.
  • Our kits are highly indestructible and are covered with an amazing warranty.
  • Our kits feature stainless steel diaphragms which not only resist the elements, but endure the harshest high pressure conditions.
  • Our kits feature standard pipe threading and line sizes so you wouldn’t have any trouble finding parts at any American hardware store.

As horns and horn kits increasingly become an inevitable option for modern truck owners, you can count on HornBlasters to continue providing you with only the highest quality horn kits as well as our first class customer service.

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