AirChime K Series Train Horns

K series train horns were unveiled in the year 1954. It is however much more refined compared to the P horn series. The horn was adapted from the kettle-drum and from which the K comes from. Each horn uses a dual disk diaphragm that comes with a silicone layer at the edges. Unlike the P horn series, it makes an air tight chamber in between the diaphragm.

The idea behind Robert Swanson's design was to create a sound that would resemble a steam powered engine. This also includes a lift up in the pitch as the air supplied is increased. What Swanson had in mind then was that the effect will be provided by the kettle drum scheme. It actually did not; however, it virtually eliminated the drop in the pitch which is present in almost all the horns, which is a significant accomplishment already.

K series horns were supplied in three chime configuration as well as five ever since they originated. Both designs were tuned based on the government authorized D# minor musical tones. A significant change on the line of the K series horn was made in 1977. Robert Swanson and Dean Ellsworth, who worked for Amtrak, labored together as well in the year of 1975 to modify his K5s. His idea is to create a horn which would resemble the sound of the previous M5 horn for the new locomotives of Amtraks.

After the bells 3 and 4 were bored out, the K5 became a horn which plays the D# major 6th tone, a step which is indeed higher compared with the C# major 6th of the M5's. The pioneering K5LA prototype however was used in 1976 as the new train horn for the Chessie system. This horn design disappeared unfortunately after a short period of time.

A machine for die-casting which was purchased by AirChime as well as the die-cast K5LA horns started to show up in 1977. The very first die-cast K5LA train horn was shown to Deane Ellsworth to be used on Amtrak. Today it was kept in a personal compilation. All K5LAs, except for the prototype, and after 1976, all the K series train horns manufactured are die-casts.

The die cast train horns keep true to Swanson's specifications, though the sand cast train horns have the tendency to come up with a mellow musical tone to the horns. The musical chords of the K horn series stayed the same throughout their service lives, unlike the P horn series. There were no notable changes done to the K series horn ever since the K5LA and the die-cast K train horns were introduced.

Construction

Like the P horns, K horn series have singular diaphragm housing. The caps are bolted on the back of the units and the whole mechanism is bolted to the manifold. They have smaller bells but the throat are wider and the diaphragm housing is larger compared to P horn bells. The bell's flare is fundamentally a supporting flare starting closely near end of the bell.

The numbers on the bell and the couple of markings on the caps are the only marks that can be seen. The K horns that are sand-cast have "Made in Canada" or "AirChime" cast into caps at the back while the die-cast ones have "30109" and "AirChime" cast at the caps.

The K horn series have a dual-disk diaphragm which was separated with a silicone ring inside it. Like the kettle drum principle, this forms an air-tight chamber in between the diaphragms and grants a better vibration on the nozzle. This eliminates the drop in the pitch as the applied air increases to most train horns, just like the M train horn.

There is also a diffuser ring which is utilized to equally share out the incoming air pressure just about the inner chamber of the K series horn. Due to the absence of the rubber gaskets, the diaphragm directly vibrates against the aluminum seats. Though it is very uncommon, the K horn has the potential to be used out to the position where it will be essential to use a machine in restoring the horns to its default spec before it is usable again.