Advanced Train Administration and Communications System (ATACS) is an

Automatic Train Control Automatic train control (ATC) is a general class of train protection systems for railways that involves a speed control mechanism in response to external inputs. For example, a system could effect an emergency brake application if the driver d ...

(ATC) system first introduced by JR East on the

Senseki Line The is a railway line in Miyagi Prefecture, Japan, owned and operated by the East Japan Railway Company (JR East). It connects Aoba-dōri Station in Sendai to Ishinomaki Station in Ishinomaki, and provides access to the central coast areas o ...

in 2011. It uses radio communication rather than traditional

signals In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...

, and works as a

moving block In railway signalling, a moving block is a signalling block system where the blocks are defined in real time by computers as safe zones around each train. This requires both knowledge of the exact location and speed of all trains at any given ti ...

system.

Technical description

Radio transmission

Communication between the train and the trackside equipment happens entirely through bidirectional

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...

communication. Radio base stations are placed at intervals of 2 to 3km and operates on four different frequency bands, used alternately to prevent inference. Radios operate in the 400MHz frequency band, with data transmitted using TDMA access method with Reed–Solomon error correction at 9.6kbps. The radio system are based on proprietary standards with encryption.

Ground equipment

Ground controller

The ground controller, being the main control unit of ground equipment, is responsible for the identification of train locations based on information received from the trains, route setting, control and interlocking, train interval regulation, and boundary control and train entry/exit handover.

Train existence supervision equipment

Connected to the ground controller, the train existence supervision equipment is responsible for controlling line occupation of trains. It also maintains safety in case of system failure and during recovery operations by using train identification assigned to each trains to track occupation even if other equipment is out of service.

System supervision equipment

The system supervision equipment monitors the operating status of the ATACS system and has functions to change settings such as temporary speed limits in increments of 5 km/h. The system supervision equipment is also responsible for setting track closures, setting

single-line working On a railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicle ...

, and routing maintenance vehicles.

Field controller

The field controller connects trackside equipment such as switches, level crossing equipment, radio stations, and detectors to the ground controller.

Onboard devices

Every train is equipped with an onboard device which is responsible for determining the train's position. For more precise position tracking, a

balise A balise is an electronic beacon or transponder placed between the rails of a railway as part of an automatic train protection (ATP) system. The French word '' balise'' is used to distinguish these beacons from other kinds of beacons. Balises a ...

is installed every kilometer. This information, along with the train length is periodically transferred to the ground equipment. Therefore, no

track circuit A track circuit is an electrical device used to prove the absence of a train on rail tracks to signallers and control relevant signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind t ...

s or

axle counter An axle counter is a system used in railway signalling to detect the clear or occupied status of a section of track between two points. The system generally consists of a wheel sensor (one for each end of the section) and an evaluation unit for c ...

s are necessary. The onboard device is also responsible for calculating the brake intervention curve required to stop the train at the limit of the limited movement authority (LMA), the area in which the train is permitted to move. It takes the individual train's braking performance, track gradient, curve, and speed limit into consideration to perform this calculation. Similar to earlier

systems, ATACS uses

cab signalling Cab signaling is a railway safety system that communicates track status and condition information to the cab, crew compartment or driver's compartment of a locomotive, railcar or multiple unit. The information is continually updated giving an e ...

. A cab display shows ATACS information required for driving, such as the distance to limit of the LMA, the maximum allowable speed as permitted by the brake curve, and the route set.

Similar systems

ATACS has been compared to ETCS Level 3

Usage

ATACS is deployed on the following lines: *

Saikyō Line The Saikyō Line ( ja, 埼京線, ) is a Japanese railway line operated by the East Japan Railway Company (JR East). It connects Ōsaki Station in Shinagawa, Tokyo, and Ōmiya Station in Saitama Prefecture. The line's name is an abbreviation o ...

( Ikebukuro –

Ōmiya Ōmiya 大宮 is a Japanese word originally used for the imperial palace or shrines, now a common name, and may refer to: People *Ōmiya (surname), a Japanese surname *Ōmiya, or is a female character in ''The Tale of Genji'', an 11th-century nove ...

)

References

{{Japan-rail-transport-stub Rail transport in Japan