What do three displays and four displays mean in railway signals?

Three display, (red light, green light or yellow light) The passing signal of the automatic block section of China's railways is three display signals. Four displays (red light, green light, yellow light or yellow green light) are suitable for passing signals in railway speed-up and high-speed sections.

According to the number of display meanings, signals are divided into single display, double display, triple display and multi-display.

1, single display-outbound, route repeat signal and interrupt signal are all single display signals.

2. Second display-The warning signal is the second display signal (green light or yellow light). Predict and display the signal of prohibition of entering the station, passing or protecting.

3. Three-display-the passing signal of automatic block section of China's railway is three-display signal. (Red light, green light or yellow light)

4, four display-suitable for railway speed, high-speed section of the signal is four display signal. (Red light, green light, yellow light or yellow-green light)

Extended data:

The consistency between railway signals and road signals is that the red, yellow and green in the basic colors of signals have the same meaning, red means stopping, yellow means paying attention or slowing down, and green means running at the specified speed.

1, red light is used for trunk lines and shunting, which means parking.

However, if it's not a red light, don't worry. If the main signal of the signalman is allowed to display red light and the signal machine is allowed to display blue light, it means that the train can pass the signal machine at a speed not exceeding 20km/h without stopping.

If the red flash is displayed on the hump color light signal and its repeater, its significance is to command the locomotive to retreat from the hump;

A red light is displayed on the main body of the incoming signal, and a month's white light is displayed below it, indicating that the train can cross the signal, enter the station at a speed not exceeding 20km/h or get ready to enter the station. When the above three conditions are not met, the train must of course stop outside the signal when it sees the red light.

2. If the passing signal in the interval turns yellow, it means that the train needs to slow down or prepare to stop, because the next signal after the yellow light may be a red light.

The yellow light indicates that the train has entered the main line of the station and is ready to stop. If there are two yellow lights, it means that the train has entered the side line of the station and is ready to stop. If the yellow light flashes together with the yellow light, it means that the train enters the station through the turnout above 18, and crosses the opened signal, and the route protected by the signal passes through the straight position or lateral position of the turnout above 18.

If the signal is green and yellow, it means that the next signal is yellow, which plays a warning role. The warning signal of signal circuit breaker lights yellow, indicating that the main signal circuit breaker is red and the train should stop. The switch indicator lights yellow, indicating that the switch is open horizontally.

The green light is easy to understand, which means that the train should run at the specified speed. However, on the outbound signal machine, if there is a semi-automatic blocking section or an automatic inter-station blocking section in the outbound direction, two green lights will be lit to mark the road to the semi-automatic or automatic inter-station blocking section.

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