Main Signals
A main signal (主信号機 shu shingōki) protects a section of track (known as a block). A protected section is in advance of (内方 naihō) the main signal. The section behind the main signal is called 外方 (gaihō). However, under the non-automatic block system a starting signal has no protected section; it only indicates that all turnouts on the route to the mainline are switched correctly. Under the non-automatic block system trains cannot leave a station without an appropriate token, even if the starting signal is clear.
Home, starting and block signals on Japanese railways are usually lights composed of three colors (green, yellow and red). The composition of the lighted colors shows the speed limit of the protected section.
G is a green light, Y is yellow and R red:
| Aspect | Name | Description |
|---|---|---|
| ●● Double green | High-speed clear (高速進行 kōsoku shinkō) | The high-speed clear signal is used only on the Hokuetsu Express Hokuhoku Line, and indicates that Hakutaka Limited express trains may travel over 130 kilometres per hour (81 mph). This signal will also be introduced on the Narita Rapid Railway. |
| ● Green | Clear (進行 shinkō) | Trains may proceed at line speed (for example, on the Hokuhoku line the speed limit is 130 km/h. |
| ●● Green/yellow flashing | Limited speed (抑速 yokusoku) | Used only between Shinagawa and Yokohama on the Keihin Electric Express Railway, but it will also be used on the Narita Rapid Railway. It indicates a speed limit of 105 kilometres per hour (65 mph). |
| ●● Green/yellow | Reduced speed (減速 gensoku) | Displayed when the next signal displays restricted speed (YY) (or caution (Y), in the case of a short block section or poor siting of the next signal. The speed limit is 50–75 kilometres per hour (31–47 mph) except for the Kintetsu (95 kilometres per hour (59 mph)) and Meitetsu (85 kilometres per hour (53 mph)) lines. |
| ● Yellow | Caution (注意 chūi) | Displayed when the next signal displays stop. The speed limit is usually 40–55 kilometres per hour (25–34 mph) (except Kintetsu and Meitetsu, where it is 65 kilometres per hour (40 mph). |
| ●● Double yellow | Restricted speed (警戒 keikai) | Displayed when the distance to the next signal is unusually short, another train is running in advance of the signal or the safety overlap at the next signal is shorter than normal. The speed limit is typically 25 kilometres per hour (16 mph). |
| ● Red | Stop (停止 teishi) | Not to be passed, except if permitted (無閉塞運転 muheisoku unten). If permitted, a train can continue at a maximum speed of 15 kilometres per hour (9.3 mph) after stopping for one minute. |
| Left - the order of changing signal aspect of five-aspect color light signal Right - an example of blinking signals |
|
If a signal lamp has burnt out, the signal will display its most restrictive aspect. If no lights are showing a signal is to be treated as stop, and may not be passed until a substitute signal is in place. Since the lights are all black, this situation is referred to as a "crow" (カラス, karasu).
Many semaphore signals were formerly used, which were controlled by a hand lever. Few semaphores remain in Japan. On 28 July 2005, the last semaphore signals on the JR lines at Rikuchū-Yagi Station were replaced by colored lights. A few stations are still equipped with semaphore signals on the Tsugaru Railway Line, the Fukushima Rinkai Railway Main Line and the Niigata-Higashi industrial line.
Read more about this topic: Japanese Railway Signals, Fixed Signals
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