Blowing a Train Air Horn
Train air horns are available as automotive aftermarket enhancements. Most often, they are sold as a complete, package which the industry refers to as a kit. Kits come with all of the components needed as well as a set of very detailed instructions which make it possible for enthusiasts who know their way around an automotive repair shop to install the device themselves.
A number of manufacturers create train air horns and package them for sale via a wide variety of aftermarket and enthusiast channels. Some are even made by companies who make the horns used on modern-day locomotives. Regardless of who is making it, the kit contains an air compressor, an air tank, horns that are referred to as trumpets, an air valve and the tubing and wiring to put it all together. They will also generally have an air gauge so you know the volume of compressed air the tank contains.