How do train whistles work?

Question

How do train whistles work?

Answer 1

Air goes through a hole.

Answer 2

Now that we know how they work, let us keep in mind that they don't always work.

When running in heavy snow the throat of the horns get clogged with snow and usually quit altogether or their output is severely reduced to the point of uselessness.

That is why the "stop" and "look" is in the admonition 'stop, look and listen' when crossing any railroad tracks.  The "listen" part doesn't go very far in a snow storm.

Here's a star for a safety question.  Thanks for asking.

Answer 3

it's a pressurized hose , that whistles , not electronic horn

Answer 4

...with SCIENCE!

Answer 5

you mean a steam whistle? through pressure-- heat expansion pushing towards a tiny hole...

Answer 6

Indeed, modern air horns use compressed air, as Andy said.  There is also a movement to being equipping locomotives with electronic horns, I think, but I'm not sure it has really ever caught on yet.  Anyway, the venerable steam whistle on steam locomotives simply uses the steam produced by the locomotive to produce that classic high/low-pitched sound.

Answer 7

steam is released into the whistle and it is forced out just like when you blow a whistle.

Answer 8

compressed air, like what is in an air tank that you fill up your tires with, is released when the engineer pulls the rope (which opens a valve allowing air to flow into the whistle. when it does, it passes over an angled surface, like in a regular whistle, and creates a whistling noise, it's just much louder because of the great amount of air moving over a larger whistle.

Answer 9

They use compressed air on modern day locomotives.I push the button or pull the lever and up to 150 lbs. or air pressure blows the horn and hopefully gets your attention.On new engines it also turns on the bell.

Answer 10

If you really are interested in the science behind them or building them, you should register with the Yahoo Group:

http://groups.yahoo.com/group/steam-whis...

Answer 11

The newer GE engines actually use a recording of the horn and bell.  This eliminates moving parts.