With the Üsküdar Ümraniye metro line, which was put into service in Istanbul, we often hear the word driverless metro. So how do these vehicles provide driverless transportation? We will explain this in our article.
The positions, directions and movements of the subway vehicles are provided by the signaling systems. The Communication Based Train Control System (CBTC) is used for these vehicles. This system is very advanced and safe to use, the margin of error is close to zero system. They are able to communicate both the exact location of the train and the remote control of the train more accurately and faster than traditional signaling systems by communicating with the stationary and instant data exchange between train and center. The subunits of these systems are as follows;
Automatic train protection system (ATP): a control system used to help prevent collisions by automatically controlling the maximum permissible speed at which a train can travel at any time according to its movement authority.
Automatic train monitoring system (ATS): monitors trains, adjusts the performance of individual trains to edit schedules, and provides service tuning data to minimize the drawbacks of otherwise irregularities.
Automatic train operating system (ATO): an operational safety enhancing system used to assist in the automatic operation of trains. Essentially, this system is an important parameter to ensure the safety of people.
Automatic train control (ATC) automatically performs automatic signal processing, such as route setting and train arrangement. ATO and ATC systems work together to protect trains with a defined tolerance. This combined system instantly adjusts the operating parameters of the train to and from the defined time interval, such as power on the go and the station residence time.
Apart from all these systems, the signaling ratings of the trains are determined by the automation levels (GoA) used. GoA (Grade of Automation) systems vary in the 0-4 range. The driverless subway system is located in GoA 3 and 4.
Now let's examine these systems.
GOA 0: Automatic train protection System without manual operation system
The safety and efficiency of train movements is under the control of the train driver. Movement authorization, including route locking and maximum speeds, can be granted in a variety of ways, including:
Roadside signals and visual warning signs,
- Fixed working rules,
- It consists of commands consisting of verbal instructions through personal or voice communication.
GOA 1: Manual working system with automatic train protection system
- ATP allows the train to stop suddenly in case of emergency against identified dangers.
- Route determination, train interval, line end, progress towards the specified direction are made automatically.
- Train integrity can be controlled, operations such as overspeed control, door opening and closing, and so on.
- The train driver is responsible for giving the train acceleration, deceleration and door opening / closing commands and monitoring the conditions of the line in front of the train.
GOA 2: Semi-automatic train operation
- The system is provided with the train driver, ATP and ATO in the cabin.
- At this level, the train driver monitors the conditions on the train line and only allows the movement by closing the door and pressing the train's departure button. All the remaining operations are provided by ATP and ATO systems.
GOA 3: Train without driver
- The system is provided with ATO and ATP.
- A train attendant gets on the train to support passengers and carry out rescue operations when necessary.
- The train attendant does not need to be in the driver's cabin, as the systems control all movement and line-long hazards.
GOA 4: Unaccompanied train operation
- No driver or attendant is required for normal operation on the train.
- There is no need for a driver's cabin in the vehicle for this system.
- System reliability should be high enough to avoid the need for train driver intervention.
Resources
1.How does a driverless subway system work, Siemens, Munich, April 2012
2.Press Scarce Metro Automation Facts, Fights and Trends, UITP
3.Increasing Levels of Automation with CBTC IRSE Seminar 2016 - CBTC and Beyond Dave Keevill, P.Eng.
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