Japanese railway signals

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Japanese railway signals, according to the ministerial decree defining technical standards of railways (??????????????????, Tetsud? ni kansuru gijutsu j? no kijun wo sadameru sh?rei), are defined as indicating operational conditions for railway staff driving trains.

Japanese signalling was initially based on British railway signalling, and Japanese railway signalling continues to be based on the UK route signalling system. However, as signalling has advanced to meet the requirements of the system (and due to the influence of the United States), the Japanese signalling system is a mixture of route signalling and American speed signalling.

Video Japanese railway signals

Fixed signals

Main signals

A main signal (???? shu shing?ki) protects a section of track (known as a block). A protected section is in advance of (?? naih?) the main signal. The section behind the main signal is called ?? (gaih?). 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:

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" (???, 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 Rikuch?-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.

Home signal

A home signal (?????, j?nai shing?ki) permits trains to enter the station. A home signal is absolute (?????, zettai shing?ki); therefore, non-blocking operation is always prohibited. Some stations have multiple home signals, due to station layout. In these cases, each home signal has an identification number which is counted from the outside of the station. In high-traffic areas, some operators install home signals in the center of a platform track to divide the block section. Some operators treat such signals as block signals. In non-interlocking stations, there may be a No.0 block signal (in some operations, a No.1 block signal or home-signal equivalent block signal) which alternates with the home signal.

Starting signal

A starting signal (?????, shuppatsu shing?ki) permits trains to depart the station, and is an absolute signal. In some stations, there are multiple starting signals due to station layout. In such cases, each starting signal has an ID number which is counted from the inside of the station. In non-interlocking stations, there may be a block signal instead of a starting signal.

Block signal

A block signal (?????, heisoku shing?ki) begins a block section in an automatic-block system. In non-blocking operation a train can proceed past a block signal after stopping for one minute at the signal, even if the signal is "stop".

Each block signal is identified by an identification number; as a train travels to the next station, the ID numbers count down. The last block signal before the home signal is number one. Each signal is associated with the next one; therefore, it cannot be manipulated by dispatchers or signalmen. The signal display depends on the presence of a train in advance of the signal and the display of the next signal.

A block signal is a permissive signal, so non-blocking operation is allowed. A train can continue at a maximum speed of 15 kilometres per hour (9.3 mph) after stopping for one minute before a block signal displaying stop. The train must not increase speed over 15kph until it arrives just before the next main signal, regardless with signals in halfway. However, due to accidents during non-blocking operation, many operators abandoned it in favor of non-block operation with full attention (??????, heisoku shiji unten). In this system, a train driver must wait until a dispatcher instructs them by radio to proceed.

At crowded stations on high-traffic lines, a platform track may be divided into two block sections so a following train can enter the track soon after the preceding train has departed. This signal is known as a No. 0 block signal. JR East treats this signal as a part of its home signals. At non-interlocking stations of JR West and other operators, the last block signal before the station is treated as a No. 0 block signal and known as the home signal equivalent block signal. This signal is not absolute, since (unlike home signals) non-blocking operation is permitted. On ATOS (Automated Transport Operating System) lines block signals are numbered serially, regardless of non-interlocking stations. In this case, some block signals are defined as home-signal equivalent or starting-signal equivalent.

Illustration

The illustration shows typical home, starting and block signals. There are two color arrangements in a four-light signal. In this figure these two arrangements are informally marked as A and B for convenience. In addition, there are single- and six-light signals.

• In an aspect using two lights (such as YG and YY), two dark lights should be inserted between the lights to improve visibility.
• Some four-light signals (equipped with light-emitting diodes, LEDs) can act as a five-light signal.
• A two-light signal is primarily used as a starting signal on a single-track line.
• A two-light signal may consist of yellow and red lights. This is used as the home signal of a terminal station or a siding, since there is no need for a "proceed" signal. On lines where the maximum speed is about the same as the caution signal, it may be used as a block signal.

High-speed signal

There are six- and five-light high-speed signals (?????,, k?soku shing?ki) with two green lights. In a six-light signal, the additional green light is located above the yellow light; in a five-light signal, the additional green light replaces the top yellow light (eliminating the speed-restriction signal). The high-speed signal was introduced on the Hokuetsu Express Hokuhoku Line--where limited express trains travel at 160 kilometres per hour (99 mph)--in 1997; and also introduced on Keisei Narita Airport Line in 2010. Two green lights indicate high-speed (no speed limit), and one green light (proceed signal) indicates a 130 kilometres per hour (81 mph) speed limit. High-speed are displayed only for limited express Hakutaka trains using 681 series and 683 series EMUs.

Call-on signal

Normally, only one train can enter a block section for safety; however, with this rule a train cannot be coupled with another train. A call-on signal (?????, y?d? shing?ki) permits a train to enter a section already occupied by another train to enable coupling.

A call-on signal is installed under a home or shunting signal. The train guided by a call-on signal can proceed under 15 kilometres per hour (9.3 mph)--25 kilometres per hour (16 mph) on some lines--until it reached the forward train. In stations where two trains use the same track simultaneously--for example, the Yosan Line Matsuyama Station (Ehime) and the Nankai K?ya Line Hashimoto Station (Wakayama)--call-on signals are required to allow two trains on a single block section. However, this is unnecessary if the platform track is divided into two block sections (for example, the Keihan Main Line Yodoyabashi Station of the Keihan Electric Railway).

There are two types of call-on signal (position and color). Both lights are normally off, and only lit if required. Position lights use two diagonal white lights; color lights are yellow.

Shunting signal

A shunting signal (?????, irekae shing?ki) is for car shunting in sidings and car depots; it is not used for trains in operation. A shunting signal has a protected section, and a train can proceed past the signal under 45 kilometres per hour (28 mph) (25 kilometres per hour (16 mph) if the train passes a non-interlocked turnout).

There are two types of shunting signal: position (???, t?retsushiki) and color (???, shikit?shiki). The position of two lighted bulbs indicates the position-type signal. This type is used primarily on JR and third-sector railways. In the color type, green means go and red stop. Color-type shunting signals are used primarily on private railways and subways; a narrow vertical signal is often used, due to narrow tunnels.

In position-shunting signals, "go" consists of two white diagonal lights and "stop" consists of red and white horizontal lights. The two-color type uses LEDs. When the shunting signal identification sign (?????????, irekae shing?ki shikibetsu hy?shiki) is on, the indicator is a shunting signal; when the sign is off, the indicator is a shunting sign. The shunting-signal identification sign is installed below the position light.

A shunting sign (????, irekae hy?shiki or--more briefly--??, irehy?) is not a signal; therefore, its diagonal indicator is not "go" but "open" (??, kaits?). A shunting sign does not have a protected section. A shunting signal is absolute, but a shunting sign is a permissive. A train may pass a shunting sign reading "stop" only if the train is accompanied by a shunting staff; its locomotive displays a shunting car sign (???????, irekae douryokusha hy?shiki)--a single red light at both ends--at night. In some systems, shunting-signal identification signs are omitted; instead, a shunting sign uses purple (instead of white) lights in a shunting signal.

A train is allowed to travel under 25 kilometres per hour (16 mph)--a lone locomotive may travel under 45 kilometres per hour (28 mph) if it does not pass non-interlocked turnouts--under a shunting sign. A stop sign may be installed just before a shunting signal (or sign) for safety.

Subsidiary signals

A subsidiary signal (?????, j?zoku shing?ki) is an alerting signal for a main signal. A subsidiary signal does not have its own protected section. When a train driver sees a stop signal and applies the brakes, the train may overrun the signal due to a long braking distance. A subsidiary signal gives advance notice, prompting the driver to decelerate to the speed allowed by the signal.

Distant signals

A distant signal (?????, enp? shing?ki) is installed before a home signal with limited visibility and is linked to the home signal. Distant signals are primarily installed in non-automatic block sections on single-track lines. They may have two (caution and clear) or three (caution, reduced-speed and clear) displays. With multiple home signals, the distant signal applies to all.

The following lists home signal aspects and the corresponding distant signal aspects

Passing signals

A passing signal (?????, ts?ka shing?ki) is installed before a starting signal in cases of poor visibility. Its display is linked to that of the starting signal.

The relationship of a starting signal and its dependent passing signal correspond as follows (also affected by a home signal):

• Home signal stop: Passing signal caution (regardless of starting signal)
• Home signal go (starting signal stop): Passing signal caution
• Home signal go: Passing signal go

A passing signal has no red light. With multiple starting signals, there are also multiple passing signals with a one-to-one relationship.

Repeating signals

A repeating signal (?????, ch?kei shing?ki) is linked to a home, starting or block signal with reduced visibility; the repeating signal repeats its relevant signal. This signal uses lines of three white lights to indicate its relevant signal:

• Go: Vertical line
• Caution: Diagonal line (reduced speed, caution or speed restriction)
• Stop: Horizontal line

This signal only repeats the relevant signal; speed restriction is applied at the relevant signal (not the repeating signal).

On the Hokuetsu Express Hokuhoku line (with high-speed signals), two repeating signals are used vertically; both signals display vertical lines for high speed. For other signals, only the lower repeating signal is used.

For underground lines where a round repeating signal would be difficult to install, a colored-light signal with a purple light (which is always on) may be used. This signal matches the relevant one.

Indicators

A signal appendix (?????, shing? fuzokuki) is attached to a home, starting or shunting signal, complementing its condition.

Route indicator

In principle, an independent home or starting signal must be installed for each route. If this proves difficult, one signal can be used for multiple routes. In this case, a route indicator (?????, shinro hy?jiki) displays the route a train is permitted to follow.

A position-type route indicator displays the route by light position. The relative position of the lighted bulbs indicates the route (with a maximum of three); if the left light is on, the train will take the left route. Some route indicators display the track number of the route or an arrow.

Rail indicator

A position-type rail indicator (?????, senro hy?jiki) is attached to a shunting sign.

Preliminary route indicator

If there are multiple routes ahead and corresponding home (or starting) signals have poor visibility, a preliminary route indicator (?????, shinro yokokuki) is installed below the signal one block before the home (or starting) signals. A preliminary route indicator advises the route displayed by the relevant home (or starting) signals.

Some private railway companies use arrow signs, or Kanji or Katakana character signs from the first letter of the branch-line name.

A track-number type preliminary route indicator (??????????, shinro yokokuki bansen hy?jit?) advises the route by number. If a train is allowed on track #3, the track number display shows 3; the number's color matches the main signal to which the preliminary route indicator is attached.

Train-type sign

A train-type sign (???????, ressha shubetsu hy?jit?), transmitted from an onboard device, is attached to a starting signal and shows the type of train that can pass it. It is mainly used by large private railway companies in stations with passing loops, express stops or turn-back stations. The sign type depends on the operator; character and number signs and symbols are used.

Disused signals

When a fixed signal is out of use, the lamps are extinguished and:

• A white cross placed over the signal, indicating it is to be ignored
• A plate or cover is placed over the signal, obstructing it from view
• The signal is turned aside, so it does not face trains

Maps Japanese railway signals

Cab signalling

A cab signal (????, shanai shing?) is a device displaying a signal in a train cab. The Yamanote Line, Keihin-T?hoku Line, Shinkansen and some rapid transit lines use cab signalling. For example, on the Yamanote line there are lamps around the speedometer; the lamp corresponding to the current maximum speed is lit. On the Shinkansen, cab signals were introduced because it is difficult to see track-side signals at high speed.

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Temporary signals

Temporary signals (?????, rinji shing?ki) are installed in work areas to indicate temporary speed restrictions. Whilst these resemble signs, they are technically classed as signals.

Speed restriction warning

A speed restriction warning indicator (???????, jok? yokoku shing?ki) advises a temporary speed restriction. The signal is a combination of white and black triangles, and the speed limit is shown below the signal. Some operators use fluorescent orange instead of white. The signal is often called a "Mitsubishi", because the white part of the signal resembles the triple-diamond logo of the Mitsubishi group.

Speed restriction

A speed-restriction indicator (?????, jok? shing?ki) is installed at the beginning of the section to which the speed restriction applies. The signal is a yellow circle, and the speed limit is shown below the signal.

Speed restriction termination

A speed-limit termination indicator (???????, jok? kaijo shing?ki) is a green circle placed at the end of the speed restriction. A train must observe the restricted speed until its end has passed the signal. To aid train drivers, some railway operators install a sign further on to indicate when the rear of the train has cleared the restriction.

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Hand signals

A hand signal (???, teshing?) is used when signal equipment breaks down and a replacement is not yet installed. A flag, lamp, sign or similar device is used.

Substitute

A substitute hand signal (?????, daiy? teshing?) is used instead of hand signals when a home (or starting signal) is out of order. At some stations, an installation position is prepared in advance.

Passing

A passing hand signal (?????, ts?ka teshing?) is used to substitute for a passing signal when the latter is out of order.

Temporary

A temporary hand signal (?????, rinji teshing?) is used when hand signals (other than substitute hand and passing signals) are necessary.

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Special signals

Special signals (????, tokushu shing?) are used in emergency situations:

• Fusee (????, hatsuen shing?): Flare used to indicate danger; also used to indicate stopping position for train
• Alarm signal (????, happ? shing?): Device which plays an alarm signal over the train radio, allowing it to be heard in the cab
• Flashing light signal (????, hakk? shing?): Flashing light, indicating danger

Obstruction-warning signal

An obstruction-warning signal (???????, tokushu shing? hakk?ki or ??, tokuhatsu) informs a train driver about an unusual situation on (or near) the track, requiring them to stop immediately. The signal consists of bright red lights, most often high-intensity LED lamps.

An example is an automobile detected by an obstruction detector (?????????, fumikiri sh?gaibutsu kenchi s?chi) stuck at a level crossing, activating the obstruction-warning device at the crossing. Another use is to guard against rockfalls; detection wires are installed at the bottom of cliffs, activating the signal when the wires are broken by rocks. On some platforms, emergency buttons or detection mats activate the obstruction-warning signal (mounted on the home signal) if a person falls on the track. Obstruction-warning signals are installed at the entrance of long tunnels or areas of dense traffic (such as quadruple-track sections); these activate if an accident is detected, preventing further damage.

An obstruction-warning signal is normally five red lamps arranged in a pentagon, with pairs of lights lit in sequence around the circle. This version is often called ??????(kuru kuru p?) in slang; the "kuru kuru" sound is associated with rotation (the phrase is used when twirling a finger by the ear to indicate craziness, similar to the western gesture). Another design for this signal is a vertical group of rapidly blinking red lights (often called a "Corncob"(??????, toumorokoshi) due to the resemblance).

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Railway-signal manufacturers

• Kyosan Electric Manufacturing Co. Ltd.(?????, Ky?san seisakusho)
• Nippon Signal Co. Ltd.(????, Nippon shing?)
• Daido Signal Co. Ltd.(????, Daid? shing?)

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See also

• Pointing and calling
• Category:Signal Ground in Japan

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References

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External links

• LazyJack Articles about semaphores, interlockings, block systems. (in Japanese)
• Kyosan Electric Manufacturing Co. (in Japanese)
• Nippon Signal Co. (in Japanese)
• Diado Signal Co. (in Japanese)

Source of article : Wikipedia