This page explains unique history of train horns. You will learn about multiple series of AirChime models and details about every design. Below is a timeline of some important events regarding AirChime train horns. My interest in train horns began at a young age. When I lived in California, I would venture out to the train tracks to listen for incoming trains. I protected my hearing though, with some ear buds, and slowly collected information for my new hobby. When I began using the Internet I looked at all the bulletin board systems for railroad and historical upkeep of the industry. I found a network of friends that taught me everything I hadn't already read in the books. This guide is a culmination of a lot of hard work and years of data collection.

1949: H6, H5, & N3 Models introduced 1950: Ending of the H5's, Model M created 1951: Extended production of Model M. 1952: M Finished, introduction of new base Model M. The same model is still offered today by Nathan. 1953: New Model J3 for Canadian vehicles. Swanson introduces his new Model P, based off the T5 1954: Swanson introduces the Model K. 1956: Creation of the Model MK, with adjustments for different valve pressures. 1957: Swanson elminates some Models in favor of new more adjustable models. 1969: K Cap dropped entirely from production.

The AirChime M series train horns are impressive. They were the first lineup that had a long production run from the company. The good thing is that interested hobbyists can still grab hold of a horn, albeit for a large price. The M series were contracted out to other manufacturers like Holden and Burnette. One attribute which hobbyists always laud about is the M series sound. These train horns have a great, beautiful sound which pleases the ear. This sound comes from producing well-known chords that are not dissonant.

A drawback, however, was the fact that other models like the P series and SuperTyfon were much cheaper for maintaining them on railroads. This caused owners to stop buying the train horns in favor of cheaper designs. Lots of replacement parts for the M series were quite expensive and hard to track down.

Robert Swanson developed the P series to pick up some slack in the line of horn lines. Directly influenced from his work on the T series, he wanted the P series to be sold as affordable and reliable alternatives to the M series while he worked on the promising K series horns. The P series unfortunately was never truly marketed by AirChime, although Nathan bought the designs to make their own and has been selling them off and on since 1953.

Swanson disliked these train horns, yet they were still effective and produced good sound while being very reliable over the years. These acted as competition against the M models that required expensive replacement parts. As a result, railroads loved the inexpensive P horns. In addition, P horns didn't have the six month re-adjustment calibrations that plagued the M series. While the potent P series fixed these initial downfalls, Nathan was able to fight the market against Leslie and their SuperTyfon horns. Another great aspect of this horn is the fact that internal parts are switchable between horns, because the back cap connects in place, it never requires new adjustments. You can still pick up a P horn from Nathan and Norfolk Southern is a frequent purchaser of the horn as well. 

Ironically, the P train horn is based off a standard truck horn design. AirChime updated the features and made it suitable for railways. Consisting of a bell with mounting feet, diagphragm housing and regular nozzles, the horn was fairly simple. Constructing the diagraphgm against strong gaskets allows the horn to be used with the least amount of wear.  

Assembly starts with placing the nozzle gasket on the nozzle and fitting it into place. Use the rest of the gaskets for the diaphgragm assembly. Finish off with putting in the six screws, that are all slotted screws matched with star style lock washers.  

John Leslie established the Leslie Corporation in the early 1800's. They manufactured rotary snowplows at the time. Working from New Jersey, they designed tons of steam components, famous for regulators and valves. The first of two re locations was in 1968, when Leslie moved to to Parsippany because they required a bigger production house. Nowadays, Leslie is situated in Tampa, Florida and has expanded its production for underwater vehicles, railroads and lots of other products including controllers heaters and even loud whistles.

It wasn't until the 1930s that Leslie started producing air horns. Leslie bought the rights to the Tyfon series of horns, and eventually the SuperTyfon series, from Kockums in Sweden. One of the first horns that Leslie produced for railroad use was the Tyfon A-200, which was a great seller, being in production for over twenty years. It was known by many as the "GG1" horn, since the popular GG1s were fitted with pairs of these, which they carried throughout their service lives. The A-200, probably the most popular of the Tyfon air horns, found its way onto nearly every make and model of diesel or electric engine up until about 1950. It was about this time that Airchime had released their first chime horns into the railroad market.

"Chime-Tone" horns were Leslie's answer to AirChime models. These were several Tyfons setup on the same bracket. Quickly, Leslie released the SuperTyfon chime horns and they were impressive. Because of these modern horns, Leslie was the first to have a "contemporary" chime horn, beating out the AirChime P series to the market). It had tons of great innovations such as interchangeable parts, back caps, and great construction. Qualities from the SuperTyfon have been used since then in train horns of today.

Way back around 1930, Leslie Tyfon's were some of the first train horns to be found on railroads. A unique aspect of the horn design was the single-note fabrication. There was just the horn itself, a back cap and a single diaphragm. Both sound chambers and other portions of the horn were made different from the bell, attached to the base. Once you have a Tyfon horn together, there is really no need to take it apart.

The A-200  156 was the most popular Tyfon horn out there. It was mainly used on road locomotives. It also appeared on various young diesels and locomotives from the 1930's  to 1960's. There were also A-125's found on railroads and even A-75's which were the rarest and used only as backups. Dual Tyfons were tried unsuccessfully to become mainstream but failed to really catch on. You can still find some of these uncommon dual designs around at a high price. 

The first thing to be careful of when working with a Tyfon is the disassembly. To disassemble the horn, loosen the lock nut on the diaphragm housing. Then, apply air to the train horn kits and while the horn is blowing, unscrew the back cap. Now that you have it apart, check the internal seat and nozzle to be sure they are level with no low spots. These two surfaces should be in the same plane with each other.

If you are working with metal diaphragms, you may notice that the diaphragms are slightly convex to one side if you place a straightedge over them. This is normal. When assembling a horn using metal diaphragms, make sure the convex side is facing the nozzle, and the leaf with least wear is against the nozzle. This aids pressure against the nozzle, forming the seal necessary to allow the diaphragm to start oscillating. Typically, three disks are used in these horns. If working with a plastic or rubber-coated plastic diaphragm, there will be a step on one side of the diaphragm. This step should be facing the nozzle. Just like the convex side of the metal diaphragms, the step aids in forming a seal against the nozzle. Also, no matter what diaphragm you are working with, if it's cracked, severely deformed, or bowed out in the wrong direction (common with rubber-coated diaphragms), it will need to be replaced.

Now that the diaphragm and nozzle have been checked, the horn needs to be assembled and voiced. Take out the diaphragm and run the back cap in all the way. If it doesn't go all the way and rather gets stuck part way, the threads may need to be corrected. Once this is done, reinsert the diaphragm and apply anti-seize to the threads. Put the back cap on and tighten it to just hand tight. Now, with air applied that is 10-25 pounds BELOW operating pressure, tighten the back cap until the desired sound is blown. Tighten the lock nut and test the horn at full pressure. If it doesn't sound correctly from low to high pressure, the back cap will need to be readjusted.

In addition, watch where you are blowing the horn. Permanent ear damage can occur with a reckless abandon of air horn usage. Imagine if your neighbor installed a horn and kept blowing it at your house every morning at five. You would get no sleep! You have to be mindful of your surroundings or others will suffer with your new toy. Keep it away from children and never blow the horn when you are driving near others. This scare tactic is popular but dangerous. People can get scared and crash into other cars or their hearing can be sacrificed at your expense.