Train Security Devices On Japanese Trains

Traffic Lights


Four-color light signal	three-color signal	light-string switchboard signalling device	Four-color light signal indicating deceleration

In principle, lines with traffic signals are equipped with ATS (Automatic Train Stop System), which is a blockage system interlocked with traffic signals. The basic concept of a blocked section is that no more than two trains can enter a blocked section at the same time. In the closed section, speed is restricted by speed limit signs and relay signals at large curves and station terminations, etc. However, ATSs were installed to protect station terminations in the “Tosa Kuroshio Railway Sukumo Station Collision” on March 2, 2005, and to prevent overspeeding on curves in the “JR West Fukuchiyama Line Derailment” on April 25 of the same year. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) obliged all railway operators in Japan to install ATS to prevent overspeeding on curves, etc.

ATS indicator light (driver’s seat)

Example of a four-color traffic light
Four-color traffic signals are illuminated for proceeding ( blue), decelerating ( yellow-blue), caution ( yellow), warning ( yellow-yellow), stop ( red), etc.

photo	manifestation	contents of an instruction	speed limit
	progress	There’s no trains ahead of us until the blocked section four ahead.	progress
	deceleration	There’s no train ahead until three blocked sections ahead, but there’s a train ahead in the blocked section four sections ahead.	75Km/h
	caution	There’s no train ahead until two blocked sections ahead, but there’s a train ahead in the blocked section three sections ahead.	45Km/h
	vigilance	There is no train ahead until one blocked section ahead, but there is a train ahead in the blocked section two sections ahead.	25Km/h
	suspension of music, dance, etc. as a sign of mourning	There’s a train ahead of us, one blocked section ahead.	suspension of music, dance, etc. as a sign of mourning

On the Narita Sky Access Line of Keisei Electric Railway, there is a high-speed ( blue-blue) signal that allows trains to proceed at speeds exceeding 130 km/h. On the Keihin Electric Express Line, there is a speed limit (yellow-blue) signal that blinks 80 times per minute and urges trains to slow down.
Keihin Electric Express Railway has a speed limit (yellow-blue) signal that flashes 80 times per minute to encourage drivers to slow down to 105 km/h or less.
The ATS system is designed to alert the driver if he or she exceeds the speed limit for each signal section and attempts to proceed to the next blocked section, and then activates the emergency brake. This is an important safety device that helps prevent human error such as overlooking a signal indication. (See below)
Light-emitting diodes (LEDs) are used in place of light bulbs.
*For routes that use ATC (Automatic Train Control System), there are no signals because of the in-train signaling system.
*Speed limits for current signals are based on different standards for different railway operators.

[Traffic light type]

		■Departure signals This is an absolute signal to indicate that the train is allowed to depart from the station. The driver’s call for “departure progress” means that the departure signal is blue. When the departure signal is confirmed by the caution signal (yellow), the driver calls “caution for departure”.
progress	suspension of music, dance, etc. as a sign of mourning

		■In-station Signal This is an absolute signal that indicates permission for trains to enter the station. It is a signal that indicates the station master’s intention, so it cannot be operated without blockage.
caution	suspension of music, dance, etc. as a sign of mourning

		■Blockage signal This signal is installed at the beginning of an automatic blockage section. Its operation is interlocked with that of the blockage signals before and after it.
vigilance	progress

		Relay signals Relay signals are installed in automatically closed sections, on terrain with poor visibility, or at curves. The purpose is to relay signals to signals one ahead that are difficult to see. There is no speed limit on the relay signal itself.
limit	suspension of music, dance, etc. as a sign of mourning

		■Shunting Signal Equipment This is a signal that gives instructions for entering a turnout when switching trains at a rail yard or station.
switchbox	switchbox

	Induction Signal Normally, only one train is allowed in a blockage, but if two trains are to be joined together to form one train at an intermediate station, an inductive signaling device is used. Two trains are put into one blockage in the yard, and are coupled together by giving an entry instruction. The speed limit is 15km/h or less when the inductive signal is displayed.
caution

ATS

Automatic Train Stop System ( ATS)
Automatic Train Stop System is called ATS( Automatic Train Stop ) and is a security device to prevent collision and overspeed. When a train attempts to proceed beyond the stop signal or exceeds the speed indicated by the signal, the device alerts the train crew and automatically stops the train’s brakes to prevent a collision or derailment. ATS systems have been required by the Railway Business Act since 1967 to be installed by all railway operators in Japan to provide backup against human error by drivers.

ATS (Automated Transfer Station)

The device that sends information such as traffic signal indications and speed limits to the train is the ground controller ( see the photo above left). The onboard equipment checks the speed of the train to see if it is within the permissible range, and automatically applies the brakes if the speed exceeds the permissible range.

		ATS-P type The ATS-P type is a digital transmission pattern type ATS system that is standard equipment of East Japan Railway Company. The ATS-P type receives information from the ground unit and calculates a real-time pattern (speed change curve from the start of braking to deceleration/stopping) based on the braking performance and travel distance of the own car, and performs speed verification by onboard equipment. This method has a proven track record of successfully reducing train spacing without compromising safety.
ATS-P type on-board unit	ATS-P indicator light (driver’s seat)

ATS-PN is installed on the Chuo Rapid Line, Chuo Sobu Line, Tokaido Line, Keiyo Line, Yokosuka Line, Saikyo Line and other major lines in the Tokyo metropolitan area that have not been converted to D-ATS. ATS-PN type (encoder omitted no-power-supply ground system) is installed on the Musashino Line, Kawagoe Line, Hachiko Line, Chuo Higashi Line, Itsukaichi Line, Sagami Line, Tsurumi Line and other lines with low train density, and is compatible with them.

Multi-Variable Signaling ATS
The multivariable signaling ATS continuously checks at a constant speed in accordance with the present signal. Even if the speed limit is increased by the current indication up after the speed limit of the warning signal, the warning speed limit continues until the train passes the next ground junction and the information is received. To release it, it is necessary to press the ATS confirmation button to cancel the verification, which has the disadvantage of causing delays on routes with high train density. Odakyu Electric Railway and Keio Electric Railway have adopted this system, and Keio Electric Railway has already switched to Keio ATC on its Sagamihara Line, and plans to switch to ATC on all Keio Main Line and Inokashira Line lines as well. Odakyu Electric Railway is also planning to switch all of its lines to Odakyu D-ATS-P in fiscal 2013 after repeated tests on the Tama Line. For more information on Odakyu D-ATS-P, please click here.

Other ATS
Tokyu Corporation used to use a unique type of ATS called track current type ATS, but it is currently used only on the Tamagawa and Ikegami Lines. Other lines have changed to CS-ATC. Tobu Railway uses the multi-variable and two-stage pattern verification type TSP system, but plans to install CS-ATC between Ikebukuro Station and Ogawamachi Station on the Tojo Line. Seibu Railway and Sagami Railway use the continuous verification type AF track circuit system, but Sagami Railway plans to switch to the ATS-P system ( JR East). The ATS used on Keihin Electric Express Railway, Keisei Electric Railway and Toei Subway Asakusa Line is the C-ATS/i-ATS type, which uses digital transmission from the track circuit to ensure safety by performing continuous speed verification according to the current indication with more detailed information than the conventional type.
Click here for a list of safety devices by railroad.

JR East type Digital ATS ( D-ATS-P type)

		Digital ATS is the latest type of ATS used on JR East’s conventional lines. Conventional analog ATSs are ground-based stairway control systems that display the maximum speed directly from the ground equipment, but the D-ATS-P type transmits the location where the train should stop from the ground equipment to the train, and the onboard equipment searches and displays the optimum speed and speed pattern from the database held in the onboard equipment after knowing the current location of the train. The onboard equipment searches and displays the optimum speed and speed pattern from the onboard equipment’s database.
D-ATS-P type onboard equipment	D-ATS-P type ground terminal

During deceleration, the system is switched to the same on-board pattern control as the ATS-P type, enabling braking to be handled in accordance with the performance of the train. This system has been adopted on JR East’s Keihin Tohoku, Negishi, Yamanote, and Yokohama lines, and is scheduled to be replaced by the ATS-P type on other lines in the future.

Automatic Train Control ( ATC)

Automatic Train Control ( ATC ) is a security device that automatically controls the speed below the speed limit as a development of ATS.
ATC was first used on the Tokaido Shinkansen, which started service in 1964.
Shinkansen trains operate at a maximum speed of 210 km/h (at the time), making it extremely difficult to see traffic signals during high-speed operation.
Also, it takes several kilometers to come to a complete stop after the brakes are applied, so ATSs on conventional lines cannot ensure safety.
Therefore, a system was developed to automatically reduce the speed below the signal indication when the train is operating at a higher speed than the signal indication by using the in-train signaling system ( CS-ATC : CabSignal-ATC ).
The exterior of the train is characterized by the absence of signals installed on the side of the tracks.

80Km limit and progress indication (CS-ATC on-board signal)

This is the current standard specification of ATC.
The type of ATC varies among electric railway companies, but the ATC on-board unit of the train receives the information (e.g. blockage situation in front) from the ATC ground unit installed on the rail, and the on-board unit determines the optimum speed and indicates the speed. There are differences in the number of speed pattern steps at this time. The Tokyo Subway (formerly the Teito Rapid Transit Company) began long-term testing of the Wayside Signal-ATC system on its Hibiya Line, which opened in 1961. Currently, the Ginza and Marunouchi Lines have adopted this system, and the CS-ATS system has been used on all lines since 2003, including the Fukutoshin, Hanzomon, Yurakucho, Hibiya, and Tozai Lines. Tokyu Corporation has adopted the ATC-P type on the Denentoshi Line, Oimachi Line, Meguro Line, and Toyoko Line (ATC-P type).

ATC on-board (red circle) and ATC device (CS-ATC) on the right side

Automatic Train Operating System ( ATO)

Automatic Train Operation (ATO) is used in Tsukuba Express, Tokyo Subway (Namboku Line, Fukutoshin Line, Marunouchi Line), etc. All of them are designed to give priority to the driver’s operation as a support device for one-man operation sections that are equipped with platform doors. On the Namboku Line, for example, there are three automatic modes: ” Normal “, “Recovery” and “Slow”. In the recovery mode (to recover from train delays), trains run at +2km/h above normal operation (3km/h below the ATC speed limit), and in the slow speed mode (to delay trains), trains can be automatically controlled to run at -10km/h below normal operation (15km/h below the ATC speed limit).
The red circle in the photo is the ATO exit button of Toei Subway Type 6300 which operates on the Namboku Line.

ATO entry button

Constant Speed Operation System
The constant speed driving system was a method to control the speed by the magnetic amplifier, the variable resistance, and the thyristor, etc. of the field current of the field current of the winding coil of the double winding commutator motor until the VVVF inverter control system appeared, but after the VVVF inverter control system appeared, the constant speed driving can be achieved comparatively easily by fixing the frequency. In the case of E231 series, “power run” and “coasting” are automatically performed by adjusting the mass controller handle to the maximum notch of “power run” and pushing the “constant speed” button. This enables the train to maintain the constant speed without operating the mass controller handle, and the overall speed can be increased. The procedure of constant speed operation is different in other train series, but the purpose of rationalization is the same.

Fixed speed operation button

The red circle in the photo above is the constant speed operation button of the Keio Inokashira Line 1000 Series.
~~By pushing the button at any speed, the speed~~ is maintained. ~~It seems to be used mainly in the express train.~~

Train Automatic Stopping Controller ( TASC)
TASC ( Train Automatic Stopping Controller) is an operation support device that automatically applies the brakes when a train stops at a station to make the train stop at a fixed position on the platform. The system generates a speed pattern by receiving distance information to the stopping position from the ground terminal installed in front of the station, and controls the brakes so that the actual train speed follows the pattern.
This system is used on the Ginza, Marunouchi, Namboku, Fukutoshin, and other lines of the Tokyo subway system, and on the Meguro, Ikegami, Tamagawa, and other lines of the Tokyu Corporation subway system.

Overrunning Prevention Devices
Overrunning prevention devices are installed at terminating stations with particularly short running margins and at stations where trains enter and exit at the same time.
Multiple ground controllers check the speed of each train, and if a train passes over the speed limit, the emergency brake is activated to stop the train. They are installed at Shinjuku Station on the Odakyu Electric Railway line, Shinjuku Station and Takaoyamaguchi Station on the Keio Electric Railway line, and Shibuya Station and Kichijoji Station on the Keio Inokashira Line.

Erroneous departure prevention device
If a train ignores the stop signal and departs, this device immediately applies the brakes to stop the train.
This device is installed in places where there is not enough room between the signal and the point (turnout) and the train cannot be stopped by the ground unit directly below the signal.

Emergency train protection device ( TE device)
The emergency train protection device is called TE(one touch emergency device ). When an emergency occurs on a train, operating the “Emergency” button automatically performs a series of train protection operations such as emergency braking, protective radio alarm, smoke bomb ignition, whistle blowing (blowing intermittently to indicate an emergency), and emergency pantograph lowering. This device, which performs quickly and automatically at the touch of a single button in an emergency, can be said to be a very effective security device. This system is used in commuter and suburban trains, such as JR East Series E231, E233, Keihin Electric Express Railway Type 2100, Sagami Railway Series 11000 and 10000, and Keisei Electric Railway Type 3000.

JR East E231 Series TE Button

emergency train stop

Dead man device
A deadman device is a security device that automatically stops a train in the event of an accident such as loss of consciousness of the train operator during train operation. The construction of the device is as follows.
In the case of one-handle type, there is a holding lever on the grip of the mass control handle, and when the hand is released, the grip of the mass control handle pops out and the emergency brake is immediately applied. In the case of one-man operation, an emergency signal is sent out by radio. There are various types because standards and specifications are not standardized.

EB (Emergency Brake) equipment
EB( Emergency Brake) equipment is an emergency train stop device that is widely used by JR companies. It is also used in Odakyu Electric Railway Type 4000, Type 3000, Sagami Railway Series 1000, Series 11000, etc. It is installed so that the mass controller handle may keep the balance of the posture while running.
The EB device is installed in the one-handed type, and if the train is not operated for more than a certain period of time (about 1 minute), the warning buzzer sounds, the warning lamp lights up, and the emergency brake is activated. The difference from the deadman device is said to be largely due to the difference between private railways, where the EB device has been mainly operated by trains, and Japan Railways (now JR), where the EB device became common as a safety measure when locomotives were operated by one person.

Train Information Management System

TIMS equipment( Train Information Management System)
TIMS is a train information management system jointly developed by East Japan Railway Company and Mitsubishi Electric Corporation. TIMS is a computer system that collectively manages train power, braking, outgoing section inspections, air conditioning management, etc.

The LCD monitor in the driver’s cab displays information on power and brake control, regenerative balance control, and driver navigation functions such as speedometers, pressure gauges, voltmeters, and kilometer range calculations.

TIOS (Train Information Odakyu management System) is called by Odakyu Electric Railway.
TICS (Train Information Control System) is called by Odakyu Electric Railway and TICS (Train Information Control System ) is called by Nagoya Railroad and JR West, but they are similar devices.
TNS (Train Navigation System) is used by Keio Electric Railway and is intended to support the operation of the train at stop stations, etc. It cannot control destinations, in-train information displays, air-conditioning, etc.

Odakyu TIOS equipment

TIS(Train control Information manegement System )
The train control information manegement system (TIS) was completed by Mitsubishi Electric Corporation in 1988 and adopted in the 03 series of Tokyo subway cars. It has become a standard feature in all new trains since then. The main function of this system is to monitor the operating status of the train’s power, braking, outgoing section inspection, air conditioning control equipment, etc., by means of serial transmission of mass control commands and normal brake commands, etc., and to collect and record fault data on a monitor display in the crew room in the event of an abnormality. The system consists of a TIS central unit mounted on the lead car and a TIS unit mounted on the middle car and connected by transmission lines.

*For more information on the Tokyo Area Transportation Management System (ATOS), please click here.

Automatic Train Control System ( ATACS)

ATACS is the world’s first train control system developed by JR East since 1995. The difference between ATACS and ATC is that ATACS has a simple configuration using radio communication with no “blocked sections”, so that trains know where they are and communicate with each other. This system enables the control of train spacing without creating a blocked section between signal devices. In addition to the current basic train spacing control functions, we are planning to add other application functions such as level crossing control and temporary speed limits in the future.
*The official announcement by JR East is here ( PDF). Technical data is here ( PDF).