Train Horn Install Instructions
I wrote this article because of my interest in having Train horn on my truck and the lack of comprehensive information on such a project. There are posts wandering about the Internet on the results of someone's mod with a picture here and there but nothing that answered the many questions that I had nor anything that approximated a "how to guide". Even the company that supplied my kit offered little useful advice. I do apologize for the pictures since I wrote the article after the horns were installed so bear with me in the photographic aesthetics area.
Secondly let me state that this installation is about air horns. Those used in industrial applications. You know the big boys that use serious air. Not the plastic trumpets driven by those Coke can compressors.
Further there are many variations of how to do things and I cannot cover every angle. I will state what worked for me.
Let’s begin.
The Cost
The installation of these horns is expensive. Plan on spending several hundred to well over a thousand when all is said and done. There are places costs can be shaved and places it shouldn’t. More on that later.
The Parts
Horns:
I installed Nathan Airchime K3LA horns on my Chevy Trailblazer These train horns cost a bit over $500. You can find train horns, marine horns, and such in many places. I have watched auctions and they all end at $500 to $1000 for a set of train horns. What do the letters and numbers for the horn mean? The K is the series of horn. Airchime made M, P and K series that I know about. I am a serious train buff so if you want more information “track” down a train enthusiast site. There’s a couple in the Yahoo Groups area. They also sell horns there. The bonus buying there is the knowledge and expertise from those with a passion for trains. The “3” means three trumpets or bells. Each is tuned to a different note. Airchime continues to manufacture K series and other horns for industrial applications such as mining. Those horns have a coverage of up to 6 kilometers and can put out 147 db at 1 meter.
The M is an older series, has a mellower sound is rare and thus more costly. The K series is what you hear on modern locomotives. It is about the loudest horn out there putting out a teeth rattling 114 decibels at 100 feet. But volume has its price. They use lots of air. That is why I chose the K series. It was Nathan’s most efficient horn for air usage and is more than loud enough for me. Efficiency is important to us because we are limited on air supply.
I also paid more because I bought from a business that refurbishes and sells these horns.
Marine horns are another option. Buy what you like and will work for you. Think about mounting and function in making a decision.
That plate supporting the horns is ½ inch thick steel.
Air Tanks:
The louder the horn and the longer you blast the more air is required. A small tank just won’t maintain the sound volume for long. A few blasts and your done. The larger the tank the more time you have and the longer the sound can be sustained. I strongly recommend 5 to 6 gallons minimal. I installed twin 6-gallon tanks on the Trailblazer Even with the K3’s a short blast drops pressure 5 to 10 psig. I bought my tanks, which came in a kit from hornblasters.com But this included all hoses, fittings, pressure switch, inlet filter and compressor. Most everything is top shelf. I had problems with the fittings, which, I will mention later.
If you opt to shop around for a tank ensure it is in good shape, you know its history and it is pressure tested. Some machine shops will pressure test the tanks for you. Avoid anything that was picked up from a junkyard or other dubious origin. These horns operate around the 120-to150-psig range or higher and are going to be mounted on your vehicle possibly near vital lines. Don’t go cheap here. Try to get tanks with a drain valve. Water will accumulate in the tank and this valve will make it much easier to get rid of it.
The Compressor:
If you’re not going the compressed bottle route then you have to put back in what you take out. For an occasional horn blaster like me the Viar compressor that came with the kits does fine. The horns can easily out run its low output, which is why I installed two 6-gallon tanks. However sounded horns like these is impressive. You only have to do it once. Trust me you won’t want to do it a lot. There are much higher SCFM compressors out there made by manufactures such as Oasis. These things can operate air tools and could drive the horns directly but probably not at their recommended pressure. Also plan to fork out $1000+ for one of these. If you don’t plan to run tools off the truck or have no need for such a beast the money can be better spent elsewhere. Like other modifications.
The intake for the compressor must be routed away from water. Mine is piped into the cab to take advantaged of dry air-conditioned air in Virginia’s wet and humid weather.
If you plan to install the compressor outside of the cab ensure it is spray and drip tight.
Pressure switch:
Unless you want to manually turn the compressor on and off while staring at a gauge then you need one of these. In conjunction with a relay it cycles the compressor to maintain proper tank pressure.
This part is critical to safe operation of the system. The setpoint for the switch should not only be based on the horn’s operation pressure but also should complement the compressor’s output. That is, the switch should not be rated outside of the compressors range or safe operating pressure for the tanks. Mine cycles from 115 psig to 140.