How Train Horns Work
The part where the diaphragm touches the nozzle is occasionally called clappers. For some horn designs, the diaphragm disk and clappers are two different parts. The M horns by Nathan and the E-2 horn by Wabco has clappers made up of smaller disks that are bolted to the bigger diaphragm disks. Additionally, it is not necessary that the diaphragm is just a singular disk. The M horns by Nathan have two to three disks for one bell, which also depends on the type of bell. Having more than one disk tends to make the joined diaphragms become rigid, also giving it superior strength, but still keeping it more elastic than a thick single diaphragm.
A diffuser can also be found inside the green compartment. The only purpose of the diffuser is to regulate the air that comes into the chamber so it could be equally dispersed. The scheme is to slow down the wearing out of one side of the disk. The M series and K series horns of Nathan and the SuperTyfon series horn of Leslie are all equip with this diffuser. The diffuser, as the picture above shows, is the disk that was held in position by three bolts (hex-key). The opening of the nozzle is beneath the diffuser.
The diaphragm housing/assembly, the head and the power chamber are other terms that you can commonly hear when discussing how the horn operates. These terms basically are the same horn components, of which consist the green compartment, diaphragm, nozzle and the enclosure that housed all this parts.
The reason why there are different terms that are used is that every company has different names for the assembly of their horns respectively. An example of which is the SuperTyfon series of Leslie which uses the term “power chamber”, on the other hand, the M series of Nathan uses the term “heads”. There was nothing specified for the P series and K series of Nathan, and also for Wabco horns so the term “diaphragm housing/assembly” is commonly used. The reuse of “power chambers” and “heads” are also common though.
It is also notable that for the P horns and K horns (though the K1L model is not included) and also for few of Wabco’s, the bell and the diaphragm assembly are attached physically. With this, discussing about the bell includes the other component as well.