What does the length of the train whistle mean?

A long sound: start the attention signal. Erchang sound: a backward signal. Three long tones: call signal.

One long sound and one short sound: steam on signal. One long and two short sounds: steam off signal. One short sound and one long sound: bow lowering signal on the way.

Two short sounds and one long sound: call signal. One long and three short sounds: alarm signal. ?

A short sound: test the automatic brake and repeat the signal. Second, short tone: ease the slip number. Three short sounds: the signal to tighten the handbrake.

Continuous short sound: emergency stop signal.

Railway signals, including visual signals and auditory signals, are the commands for train running and operation. Train whistle is the range of train auditory signals, and different train whistles represent different meanings. Long note 3 seconds, short note 1 sec, interval 1 sec. Must be carried out in strict accordance with the instructions of the railway signal.

The most important machine in human history, called steam locomotive in the early days, has an independent orbit. Railway trains can be divided into freight cars and passenger cars according to their load capacity, and there are mixed passenger and freight cars.

Trains are a typical example of human transportation using fossil energy. 1804, the world's first steam locomotive was built by British mining technician Drivesk using Watt's steam engine, with a speed of 5 to 6 kilometers per hour. Because coal or firewood was used as fuel at that time, people called it "train" and it has been used ever since.

References:

Train whistle _ Baidu Encyclopedia