The colors of railway signals are red, yellow, green, white and blue.
White: shunting signal, indicating that shunting is allowed by this signal.
Blue: shunting signal, indicating that shunting is not allowed by this signal.
Railway signals are divided into visual signals and auditory signals.
Visual signals are divided into daytime signals, nighttime signals and day-and-night general signals. Only night or day and night general signals are used in the tunnel. Visual signals include signals ~ signal indicators ~ signal signs ~ hand signals ~ locomotive signals.
Signals are divided into arm board signals and colored light signals, including entrance signals ~ exit signals ~ passing signals ~ blocking signals ~ warning signals ~ shunting signals ~ hump signals ~ route signals ~ repeated signals.
The following is a brief description of the color light signal of the three display parts.
Arrival signal: green light: main line passing. Yellow light: stop at the main line. Two yellow lights: stop at the side line. Red light: Don't cross. A red light and a moonlight light: guide the station.
Exit signal: green light: allow to start. Yellow light: the train is allowed to leave the station, indicating that at least one block section is free before running. Red light: Don't cross. Two green lights: automatic block section means to remove non-automatic block section, and semi-automatic block removal means to remove secondary line. Also used as shunting signal, white light for one month: allowing shunting through the signal.
Pass signal: a green light: the train is allowed to run at a specified speed, which means that at least two blocked areas are free before running. Yellow light: the train is required to pay attention to the operation, which means that there is a blocking zone in front of the operation. Red light: The train should stop at the signal light. The passing signal equipped with permission signal shows blue light: when the signal shows red light, the train is allowed to pass at a speed not exceeding 20km/h without stopping, and run to the next passing signal, ready to stop at any time.
Interrupt signal: red light: trains are not allowed to cross the signal. There is no signal when the light goes out.
Early warning signal: green light: indicating that the main signal is on. Yellow light: indicates that the main signal is off.
Shunting signal: white light for one month: shunting through the signal is allowed. Blue light: There is no signal shunt.
Hump signal: green light: allow locomotives and vehicles to advance to the hump at a specified speed. Blinking green light: indicates that the vehicle accelerates to the hump. Yellow flashing light: instruct locomotives and vehicles to slow down and push to the hump. Red light: the vehicle shall not cross the signal or instruct the vehicle to stop running. Red flashing light: indicates that the vehicle is retreating from the hump. One-month white light: indicating the locomotive to go down the peak. One-month white flashing light: instruct locomotives and vehicles to the no-go line.