They scare me, I don't know about you! We have all heard these loud blasts before, not good when you are trying to sleep. That penetrating sound and steady long lasting tone, its hard to mistake thats for sure.

It it designed as a warning sign for pedestrian and motorists a like. It's a good warning sign at that! They can also be used to signal other trains as well. Even to the railway station and station masters.

In vehicles and and in trucks, air horns are used, but nothing quite as exciting as that train whistle. It really does stir the imagination like no other sound I know of. Trains in general evoke a feeling of nostalgia, but the sound of a train whistle always reminds me of the train trips I took as a kid. I grew up near a railway station, my grandfather was a station master for 40 odd years.

Just like with anything, there are people or hobbyists who collect all the different types of train whistles from all the different types of trains that have been around. There is actually quite a big market for this sort of item. There are clubs as well.

Air horns for all intensive purposes all work the same sort of way. The best way to explain how they work is like this. Picture a megaphone in your head. You know what they are. They work by way of magnets, a voice coil and a diaphragm. Once it is turned on, the diaphragm starts to vibrate and that causes the loud sound waves.

The air horn is a type of speaker as well, but it pushes air out instead. The air pressure causes the diaphragm (it has one as well) to open quickly and shut quickly. This happens many many times a second. This is then heard by our ears as the steady tone we all know.

Many fanatics can even tell the difference between different models of train horns just by listening to its particular tone. The train horn pitch is changed by many variables.

Such things as the diameter of the air inlet can determine the pitch and loudness of the horn. Also the internal components and the different bell horn material can also change the tone. It could be mellow or sharp and it could also be somewhere in between. Also and this is a big one, the size and shape of the bell horn can change the tone dramatically.

Air tanks are what supply the air horns with their power. These tanks cannot hold an infinite amount of air so they do need to be refilled by a pump. A good diesel air horn will need plenty of compressed air to work, so if you are thinking about buying one of these, you will need a good 25 gallon tank.

One of the biggest markets for train horns are those who drive pickups and of course those who drive SUV's as well. There are scaled down versions that can be purchased for personal use on vehicles. These are very chrome in appearance and are extremely loud. Do not honk these in quiet streets.

These horns are also great for boating. You will need to check with your local authorities before installing this sort of horn on any vehicle as it may be illegal to use this sort of horn. Train horns can produce sounds up to 175 decibels.