Recent Advances in Circuits, Systems and Automatic Control

Functional Allocation and Door Control of ATO for the Korean Radio-based Control System

MIN-SOO KIM, YONG-KI YOON, SEH-CHAN OH and YONG-KYU KIM Radio-based Train Control Research Team, Korea Railroad Research Institute 360-1 Woram-dong, Uiwang-si, Gyeonggi-do, 437-757, KOREA [email protected] http://www.krri.re.kr

Abstract: - The Communication Based Train Control (CBTC) performs train position report immediately and movement authority transmission through wireless communications between a wayside control center and on- board vehicle computers. And it has effect of increasing the railway capacity by allowing the high-density train control through a high capacity of information transmission between the on-board and the wayside. Also, it reduces the maintenance cost because it does not use the existing circuits. The Automatic Train Protection (ATP)/ Automatic Train Operation (ATO) is fundamental train control system for driverless operation in urban rail and metro rail, and it is important role in the communications based train control system. Especially, the ATO acts as a key role for automatic operation in urban rail with short distance between stations stopping and frequently stops. This paper describes the door control including platform screen door (PSD) and functional allocation of ATO which is responsible for the automatic operation and the door control as a subsystem of the Korean Radio-based Train Control System (KRTCS).

Key-Words: - Korean Radio-based Train Control System, Automatic Train Operation, Door Control, Automatic Train Protection

1 Introduction offers safety and conveniences of passengers Railway systems are group of individuals with through the safe operations such as an accurate stop vehicles, tracks and signals, and therefore the on the station, train door/Platform Screen Door effective interaction among the subsystems is a core (PSD) controlling, and so on. role. This paper deals with the door control, the Train control system or railway signal plays a key function allocation and the design of the functional role in ensuring safety separation between the requirements of the ATO suitable for KRTCS operation in the territory and improving efficiency (Korean Radio-based Train Control System) as a of railway operations by protecting train collision subsystem of the CBTC with driverless automatic between a preceding train and a following train [1]. operation. Train control systems already operating in the domestic railways include Automatic Train Stop 2 KRTCS (ATS), Automatic Train Control (ATC), and The KRTCS consists of the ATP to ensure the limits Automatic Train Protection (ATP) using balise (or of safe train separation, ATO to provide a high transponder) and track circuit. passenger comfort including acceleration/jerk Communication Based Train Control (CBTC) limitations and automatic operation in both recently introduced in Korea is a railway signal directions, ATS to monitor trains a powerful and system based on communications and information flexible, and EI which is responsible for the technology, and consists of sub-systems such as information on locking, releasing and switching Automatic Train Supervision (ATS), ATP, route. Automatic Train Operation (ATO), Electronic Interlocking (EI) and Radio Communication 2.1 ATP function Network (RCN). •Determine train location, speed, and travel Among them, ATO system is an automatic train direction: Train location, speed, travel direction are system that can increases the commercial speed and determined by the location information with regard reduce headway of the train to provide the to fixed track-side reference point devices maximum transportability of the subway train, and (transponders with a 200 [m] interval). That is, ATP

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compensates uncertainty which is affected of location measurements inaccuracies by accumulated The ATO performs non-vital functions such as by tachometer. regulating train speed, stopping right place and door •Determine limits of safe train separation: ATP control under the supervision of ATP, and receive determines the limits of safe train separation for a state of the station, operation command, wait following train, with appropriate consideration of command, controlling train door commands, the location uncertainty (position uncertainty) of the stopping commands and fault checking by preceding train (including any rollback tolerance) communicated with on-board device. using the moving block system rather than relying • Stop train in station: When the train stops on the on existing track circuits. Speed restriction factors platform, it uses the distance from the stop point to for calculating the static speed profile include the the transponder in order to provide a comfortable followings: ride for passengers and stopping at the right location. - The permanent speed limits on section of track • Train speed control: Under the ATP speed - The temporary speed limits on section of track supervision, it controls the operation speed in - Any permanent speed restriction applicable to the accordance with target speed profile by the ATP particular configuration of train functions. - Any speed restrictions enforced on the train • Train door control: When the train stops in station, because of train-borne failure conditions it automatically synchronization to performs the train door opening and closing with the PSD. Also, it performs the train door opening and closing by communicating with the ATS.

- Maximum speed that would allow the train.

Fig.1 Moving Authority (MA) in moving block operation

Dynamic speed profile develops a speed profile Fig.2 KRTCS ATO Primary ATO functions (braking curve) based on train speed limit by section and variable data determined according to the static 3 Design and Functional Layout of speed profile. ATO for KRTCS • Emergency braking: If the train does not comply ATO of the KRTCS is allocated and designed in six with the limit conditions assigned by ATP, the ATP functions as shown in figure 2. applies emergency braking within the safe braking ATO functions, the 'Awake Train' function, is margin. Once the emergency braking is applied, the intended to awake trains which are in stabling emergency braking will be maintained. Train locations(in workshop, sidings or in the line) before movement shall be allowed after resetting the they enter service(operation) when a train emergency brake, when ATP condition is satisfied equipment is powered up and a cab is activated by • Route interlocking: Interlocking to route and remote action from the ATS. Also, the 'Sleep Train' switch is a vital function in the intelligent train function is intended to set the trains to sleep in control system that prevents the collision and stabling locations (in depot, sidings or in the line) derailment of a train, and is protected by ATP. after they leave service (operation) by remote action • Safe Braking: The minimum distance for safe from the ATS. braking is set based on the maximum stopping The following describes the details of the distance of the train emergency braking that may allocations and design of the remaining four occur in the worst case. functions except indication device.

2.2 ATO function

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3.1 Determine the ATO operating speed station and if the train fails to reach the stopping profile point at the platform, the ATO system shall jog the This function is intended to determine the operating train forward automatically until it does so. speed profile (including service acceleration/ If the train failed to stop at the right location after deceleration rate) in accordance to the train performing the automatic inching by the ATO protection profile and taking into account notably system, the ATO system request the remote inching the following factors: to the ATS for the stop at the right location. - Stopping points (target points) The ATO system which received a command to - Driving mode remote inching from the ATS shall perform the - Braking performance inching control. The ATO system shall be on - Jerk limitation standby status if the ATO system does not receive - Train Strategy and Regulation Strategy remote inching command from the ATS. - The system response time including the rolling stock reaction time

The ATO shall determine the operating speed profile in accordance with the dynamic speed profile of ATP and to enable the train to stop at the next stopping point. Also, it shall determine the operating speed profile to enable the train to stop or skip as commanded by the ATS and shall choose operating speed profile in accordance with the regulation strategy. Fig.4 Inching control functional diagram If it shall determine the operating speed profile to start a train after a stop between stations 3.3 Regulate train automatically as soon as the authorization to depart The ATO system shall deliver deceleration to the is given. rolling stock relying only on the service brake. This function is intended to transmit propulsion and braking signal in accordance with train operating profile, and shall determine the operating speed profile (including service acceleration/deceleration rate) in accordance with the train protection profile. In other words, regulate train speed means the transmit propulsion and braking signals appropriately in accordance with the train operation profile.

Fig.3 ATO profile determination diagram

3.2 Inching control This function is intended to the train stops at the right location automatically to enter the station, but if it is retried the train stops at the right location cause of failure (under-run, over-run) to stop at the right location. It is also intended to includes perform the inching Fig.5 Regulate train speed operating by the ATS operator's command when the ATO system’s automatic inching (exceed the number of retrials) was failed. 4 KRTCS door control This function is intended to command train doors If the train stopped outside of the stop tolerance, and platform doors (if installed) opening when the ATO system shall precede the train to the next opening authorization conditions are met.

ISBN: 978-960-474-349-0 301 Recent Advances in Circuits, Systems and Automatic Control

· Door Open Command: command for train doors open · Door Close Command: command for train doors close · Departure Command: Including the information messages of the next station. The message sent after confirming the train stops at the right location and includes the next station information. When the ATS sends the Departure Command, the ATO performs the door close if it is opened. Fig.6 Door control functional diagram And the command sent from the ATS to the Also, this function is intended to command train wayside ATP is follows. doors and platform doors (if installed) closing when · Door Open Command: the enable command for the train want to close the doors to depart. the door open The ATO system shall transmit opening signal to train doors and platform doors (if installed) in For the train to depart, it requires to receive a accordance with established procedures if the door departure command from the ATS and departure mode is set to be opened automatically. And the permission from the ATP. If the train has a holding ATO system shall transmit opening signal to command, the train may depart after it receives the platform doors in accordance with established release command by ATS. procedures, if the door mode is set to be opened manually and platform screen doors are installed. And the holding command is available from the Also, the ATO shall transmit opening signal to time of stopping at the right locations until the train train door and platform door (if installed) in receives departure permission by ATP. If the train accordance with the established procedures if the have the close command separately, the automatic door mode is set to be opened automatically. departure is possible when there is the departure

command by ATS and departure permission by ATP. Depending on the train driving mode, the train doors have different door modes.

Table 1 Door mode according to driving mode Driving Mode Door Mode

Driverless Auto/Auto

Auto/Auto, Auto/Manual, Auto Manual/Manual

Manual Manual/Manual

Depot(Yard) Manual/Manual

Emergency Manual/Manual (a) Door open sequence

The commands sent from the ATS to ATO are follows.

· Holding Command: command for train standby · Holding Release Command: command for release train standby

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Control (CBTC) System Design and Functional Allocations, 2008. [4] IEC 62290-1, Railway applications – Urban guided transport management and command / control systems – part 1: System principles and fundamental concepts, 2006. [5] IEC 62290-2, Railway applications – Urban guided transport management and command / control systems – part 2: Functional specification, 2006. [6] ERTMS/ETCS-class 1, System Requirements Specification subset-026-1, issue 2.3.0, 2006. [7] UIC project EIRNE, Functional Requirements Specification, GSM-R Functional Group, 2006. [8] Urban railway signal system standard (b) Door close sequence specification (proposal), Korea Railroad Fig. 7 Operating sequence of Door and PSD in case Research Institute, 2007. of auto/auto door mode [9] EN 50126: Railway applications. The specification and demonstration of reliability, The figure 7 shows the door open and close availability, maintainability and safety (RAMS), sequence when the train door mode is auto/auto 1999. mode and shows interactions between the ATP [10] EN 50128: Railway applications. wayside, the ATP onboard, PSD, train door, the Communications, signaling and processing ATO onboard, staff and the ATS. systems, Software for railway control and protection systems, 2001 [11] EN 50129: Railway applications. Communication, signaling and processing 5 Conclusion systems, Safety related electronic systems for The ATP/ATO system which is the core of the signaling, 2003. CBTC(Communication Based Train Control) [12] EN 50155: Railway applications. Electronic system is a train control system for driverless equipment used on rolling stock, 2001. operation in urban subway and metro rail, and [13] Engineering Safety Management, Issue 3, especially the ATO acts as an important element for “Yellow Book” automatic operation in urban subway having [14] EN 50159-1: Railway applications. frequently starting and stopping at the short distance Communication, signaling and processing between stations. systems, Part1: Safety - related communication This paper deals with the train door control in closed transmission systems, 2001 including the PSD and the function design of the [15] EN 50159-2: Railway applications. ATO system as a subsystem of the Korean Radio- Communication, signaling and processing based Train Control System (KRTCS) which is systems, Part2: Safety - related communication possible for the driverless operation. And the train in open transmission systems, 2001 door control, functional allocations of the ATO were [16] IEEE Std 1228-1994, IEEE Standard for performed to apply the KRTCS satisfying driverless Software Safety Plans, 1994. operation and interoperability. [17] MODURBAN, Comprehensive operational, functional and performance requirements, References: 2009. [1] KRRI, Train Control System Requirements [18] Compendium on ERTMS, Eurail Press, 2009. Specification(SRS), Ver.4.0, 2012. [2] IEEE Std 1474.1-2004, IEEE Standard for Communications Based Train Control (CBTC) Performance and Functional Requirements, 2004. [3] IEEE Std 1474.3-2008, IEEE Recommended Practice for Communications Based Train

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