What does the train mean by playing the flute twice in a row?

("-"stands for long sound, "*" stands for short sound. Long note 3 seconds, short note 1 sec, interval 1 sec. ) The same below

A long sound—

Use time:

1. When the train starts or the locomotive is moving forward (when two engines are pulling or using the locomotive, the locomotive should answer after whistling for a long time, and the locomotive will start).

2. Approaching stations, horns, bends, intersections, bridges, tunnels, pedestrians, construction sites, yellow signals, guidance signals, permission signals or bad weather.

3. Automatically block this part. You can continue to run before and after stopping at the signal, and inform the train conductor when running.

4. When the electric locomotive is being overhauled and ready to lower or raise the pantograph.

Second, the regression signal

Two long notes-

Timing of use: when the train, rolling stock and single machine start to go backwards.

Three-call signal

Three long tones-

Timing of use: when the protective personnel are required to evacuate.

Fourth, the steam signal

A long and a short voice-*

Timing of use: when the locomotive of this business requests to make up the engine and start the steam on the way (the engine should answer the same signal).

Five, off steam signal

One long and two short tones-* *

Use time:

1. When the locomotive of this service requests to supplement engine steam (the locomotive should reply with the same signal).

2. At the back of the train, when the machine is repaired and the machine stops pushing standard steam.

Six, bow on the way.

A long and short voice *—

Use time:

1. When the locomotive driver of this service finds that the catenary is faulty and is in danger of scratching the pantograph, he requests to repair the locomotive and lower the pantograph (the repair must be answered with the same signal).

2. When the electric locomotive driver finds the hand signal indicating the catenary fault on the way, he should call this signal back.

Seven, call signal

Two short and one long tones * *—

Use time:

1. When the locomotive requests to enter and leave the section.

2. When the signal needs to be displayed at the station.

Eight, alarm signal

One long and three short tones-* * *

Use time:

1. When there is a bad place on the line that endangers traffic safety.

2. When the train has a major accident or other situations requiring rescue.

3. After the train stops in the interval, it can't run immediately, so inform the running conductor.

Nine, automatic testing

A short sound *

Use time:

1. When the test brake starts to decompress.

2. When receiving the hand signal of the end of the test braking, brake and answer the anemometer.

3. In shunting operation, it means that the hand signal sent by the shunting commander has been accepted.

X. Mitigation and Slip Signals

Two short sounds * *

Use time:

1. When the test brake is released.

2. Ask the train staff to release the handbrake.

3. When the shunting signal is repeated.

Eleven, tighten the hand brake signal

Three short notes * * *

Use time:

1. When the train attendant needs to tighten the hand brake.

2. When local braking is needed.

Twelve, emergency stop signal

A continuous short sound * * * *

Timing: When the driver finds (or is told) that there are obstacles on the adjacent line, he sends an emergency stop signal to the trains running on the adjacent line. Drivers of adjacent trains should stop urgently after hearing this signal.