Whistles, Horns and Bells

"Whistles are for safety, not for playing games! You must only use your whistle when the time is right!"

- The Fat Controller, Percy's New Whistle

Whistles are steam-powered sound-making devices that allow steam engines to warn people, animals and other vehicles, or to communicate with staff. The engines also commonly use them to greet other engines or vehicles when passing by.

It is very dangerous for an engine to operate without a whistle since, unless they have one, they are difficult to hear from a distance.

Horns are the air-powered equivalent used for diesel and electric locomotives. Non-air horns are used for cars, buses and lorries.

Bells are used by steam engines, usually tram engines such as Toby. However, a lot of steam locomotives are equipped with both a whistle and a bell.

The various sounds for the whistles, horns and bells each individual engine uses can be found on their individual articles.

Trivia

 * Nitrogen Studios animated the engines' whistles to budge up and down when in use, from the thirteenth series to the sixteenth series. Though this practice has mostly gone out of use, Arc Productions still incorporated this occasionally, such as in The Adventure Begins and the twenty-fourth series episode, Emily to the Rescue. Some shorts of the online mini series done by Pixel Zoo also animate the whistles in this manner.