AUTONOMOUS SYSTEMS IN RAILWAYS-Dr. İlhami Pektaş

By 2050, the world population living in cities is expected to double, reaching approximately 6.4 billion. In other words, 70 percent of the population will live in cities. In order to keep up with such a rapid change, it is essential that our transportation systems are highly economical, high in frequency and line capacity, punctual, efficient and free from human errors.

In the future, tracks should be modernized and equipped with automatic train control security systems in order to increase the capacities of our public transportation systems and to use the systems more efficiently in existing infrastructures.

There has been a lot of work on self-driving cars in recent years. However, there are numerous complex algorithms and difficulties such as traffic conditions, safety norms, road conditions, human psychology while driving in autonomous vehicles such as taxis and trucks.

On the other hand, driverless train systems are simpler to design and applicable than driverless cars or trucks. It is easier to understand where a train is, as the route is limited to the railway line and there are only back and forth directions. Therefore, if there is no big mistake in the system, the train driver does not have to worry about another vehicle that might get in the way, as in cars.

In train automation systems;

Driver-controlled system (GoA0): The train is managed by the driver, with a light signal system on the road, without any auxiliary system. This is the most widely used system in train operation.

Partially automatic system (GoA1): The train driver has driving and braking control on the system. However, unlike the driver-controlled system, the train protection system constantly monitors the speed and displays it on the driver’s screen in order to provide statistical information for the movements of other trains in the network. In this system, the train speed is controlled and cannot go beyond the determined speed.

Semi-automatic system (GoA2): The train driver’s only job is to start the train and let it move. Then the automatic driving system is activated. The system has full control over the movement of the train between the two stations, including when the train stops on the platforms and the doors open and close. Taksim-Haciosman Metro line was built in accordance with 2nd degree semi-automatic system.

Driverless system (GoA3): The automatic driving system has full control over departure, movement between stations, automatic stopping of the train and opening and closing of the doors. The doors can be reopened automatically, if necessary, according to the situation analysis of the system. Additional trains can be put into service automatically in case of high passenger density. However, a train attendant is on board to assist the passengers and in case of emergencies. Kadikoy-Kartal Metro line was built according to the 3rd degree automation.

Fully automatic driverless system (GoA4): Unlike GoA3, the automatic driving system is completely driverless controlled and monitored. There is no attendant on the train. In the negative case, operation and intervention to train malfunctions is done by the traffic operator from the control center. When there is a breakdown that cannot be intervened in the train, the rescue train is sent to the region together with the teams in the workshop and intervened. If the train breakdown cannot be intervened, the vehicle is pulled to the workshop. Uskudar-Umraniye-Cekmekoy Metro line was built according to the 4th degree automation. In this line, all operations of the metro including acceleration, deceleration, stopping, opening / closing the doors are managed by a software.

While ERTMS manages train signals, speed and automatic brakes, ETCS controls the activation of signs placed on the road in order to collect information and provide driving instructions to the vehicle, and ATO controls the driving and braking systems of the train. ERTMS is the Backbone of Digital Trains. The name of this technology applied in the driverless train system is Communications-Based Train Control, CBTC. This technology enables the management of the entire railway line by performing communication between the train and the equipment on the line. Thanks to the combination of these solutions, trains operate in an optimized speed and their operation frequency and line capacity increase. Besides, thanks to ATO, energy is saved and time efficiency and security is increased. While a signal system and driver are required in conventional lines, lines with CBTC are operated with data. Communication between train and line equipment on lines with most CBTCs is provided by wireless communication networks such as GSM-R and WLAN. The Swiss rail system company (SBB) has developed an automatic drive system on the Bern-Olten high-speed line. Thanks to this program designed to remove unnecessary stops and reduce energy consumption, SBB calculates the optimum speed for the train and transmits it to the operator.

Driverless railway systems are energy efficient and highly economical due to the optimization of acceleration, braking, traction and power transmission. With the data produced in the control centers, the system calculates where and when the train will accelerate, decelerate and stop.

Applications in Our Country

In our country, GSM-R, ERTMS and ETCS systems operate in the high-speed trains and they increase the safety, speed, line capacity and time efficiency of the trains.

TCDD Tasimacilik carries 23.000 on high-speed trains, 49.000 on mainline and regional trains, 350.000 in Marmaray, 39.000 passengers in Baskentray and 100 thousand tons of freight every day with the new generation technologies and special digital technology applications. GSM-R, ERTMS and ETCS (GoA0, GoA1 and GoA2) systems with drivers on existing high-speed train lines operate and increase the safety, speed, line capacity and time efficiency of trains.

2nd degree (GoA2) automation system in Taksim-Haciosman Metro line, 3rd degree  (GoA3) automation system in Kadikoy-Kartal Metro line, 4th degree (GoA4)automation system in Uskudar Ümraniye Metro line, and communication-based train control and signaling systems with drivers (GoA0, GoA1 and GoA3) in all other urban lines are used.

Urban and Intercity Rail System Applications in the World

There are 62 driverless metro lines worldwide. The world’s first driverless metro was put into service in Kobe, Japan in 1981. Europe’s first driverless metro started operating in the city of Lille in 1983, two years later. The country with the longest driverless metro line network is France. It is followed by Canada, Singapore and the United Arab Emirates (UAE).

While the driverless metro network was 1030 km in 2018, it is expected that the driverless metro lines will increase to 2300 km in 2025 with ongoing and projected investments.

The world’s first driverless train that can travel at a speed of 350 kilometers per hour started service in China in 2020. The driverless train, a new product of China’s Fuxing series, will operate on the world’s first smart high-speed railway. The 10-station high-speed train line known as Jing-Zhang will connect the cities of Beijing, Yanqing and Zhangjiakou.

In Europea, The Swiss rail system company (SBB) has developed an automatic drive system on the Bern-Olten high-speed line.

The state-owned SNCF company of France plans to use driverless trains in 2023.

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