High-speed trains will have "super brains"
Wang Lin
China National Railway Group Co., Ltd. recently promulgated the "Outline of the Advanced Railway Planning for a Powerful Transportation Country in the New Era", which clearly stated that by 2035, it will be the first to complete the intelligent railway network. The length of the national railway network will reach about 200,000 kilometers, of which high-speed rail will occupy about 70,000 kilometers. ; High-speed rail trains will have a "super brain" based on Beidou satellite navigation system and 5G communication technology that integrates space, space and ground.
So, how smart is the "super brain" of high-speed trains?
1
How is the train running interval controlled today
Whether it is a general-speed passenger and freight railway or a high-speed railway, generally speaking, two parallel tracks are laid, and the left and right trains do not interfere with each other. So how do you ensure the safe operation of trains on railway lines that run from hundreds to thousands of kilometers?
We know that when a car is running on a highway, the distance between the front and rear cars is not less than 50 meters to ensure the necessary safety. Normal speed trains in my country generally run at 120-160 km/h, and high-speed trains run at 350 km/h. Such a fast speed will inevitably impose stricter requirements on the safety distance between the two high-speed trains.
The railway department divides the operating space for trains through "blocked zoning" to provide safety guarantee for train operation. The "blocked zone" is to divide the railway line into several sections of varying lengths through the track circuit. The two ends of each section are controlled by a signal and displayed on the display screen of the dispatch center. When the train is running in a blocked zone, the signal at the rear of the vehicle turns red, indicating that there is a car in this section, and the train behind it must be vigilant and not rush forward. Only when the signal in front of the train is green can it travel at full speed.
Nowadays, regardless of the mixed passenger and freight railways or high-speed railways, most of them use "automatic blocking systems." It is worth mentioning that once the "automatic blocking zone" is divided, it cannot be changed arbitrarily, which means that the automatic blocking zone is fixed, which is completely different from the "mobile block" described later.
To put it simply, the fixed automatic block zone is divided by the track circuit, and its working principle is as follows: when there is no train in the block zone, the current flows from the positive pole of the track circuit through the rail and the rail relay to the negative pole of the other rail power supply. At this time, there is current through the relay, the armature is sucked up, and the green light is turned on, indicating that the interval is free; when the block area is occupied by trains, the wheels and the track form a path, and the current is short-circuited by the wheels. Turn on the red light to remind the car behind that this section is already occupied.
On ordinary-speed railways, drivers can control the train by watching the signal changes from the signal machine. In the era of high-speed trains, due to the fast running speed of trains, drivers have no time to respond to the signals next to the line. Advanced train operation control systems must be adopted to ensure safety. As the name suggests, the train control system is a signal system to ensure the safety of trains. Using the line information provided by the ground, the distance of the vehicle ahead and the state of the route, the train control on-board equipment automatically generates the control mode curve of the allowable train speed and compares it with the actual train speed in real time. In comparison, once a train is found to be overspeeding, it will be controlled in time to ensure the safety of high-speed trains. This system cancels the signal machine beside the general-speed railway, and installs a transponder in the middle of the track, which can realize the data exchange between the train and the ground.
2
"Super brain" can greatly shorten the interval between the front and rear cars
The fixed automatic block divides the interval by the track circuit, and the key component of the "super brain"-wireless mobile block is to divide the non-fixed mobile zone by wireless communication technology. This is the essential difference between the two, and mobile block is essential for communication technology. And positioning technology is more demanding.
In the traditional fixed automatic blocking mode, the system cannot know the specific position of the train in the zone, so the starting and ending points of train braking are always at the boundary of a certain zone. In order to fully ensure safety, a protective section must be added between the two trains, which makes the safety interval between trains larger and greatly reduces the efficiency of the line.
The wireless mobile blocking technology has taken a step forward in the control of the safe interval of the train. Its functions such as information transmission, train positioning, and train integrity inspection no longer rely on the ground track circuit, thereby greatly reducing the number of equipment installed next to the track. The on-board equipment subsystem of the wireless mobile block uses speed sensors, radars, and photoelectric sensors to measure the speed and distance of the train, and combines with the ground transponder to correct the train position, which can continuously and automatically detect the train position to ensure the system Safety protection of train speed and travel interval.
In this way, the wireless mobile block system can communicate with on-board equipment and trackside equipment without interruption. The dispatch control center can dynamically calculate the maximum braking distance of the train according to the real-time speed and position of the train, so that the "length of the train + maximum Braking distance + safety protection distance" forms a virtual partition that moves synchronously with the train, which is the "moving block partition".
As the safety distance between the front and rear of the train is ensured, two adjacent moving blocks can move forward at a small interval at the same time, allowing trains to run at higher speeds and smaller intervals, realizing the "small marshalling" of high-speed trains. The goal of "high-density" transportation organization is to greatly shorten the departure interval of the front and rear vehicles, thereby greatly improving the efficiency of the line.
3
"Super brain" cannot do without "Beidou" and 5G
The wireless mobile block system can be said to be a key component of the "super brain" of high-speed trains. Its most notable feature is that it requires accurate positioning of the train's dynamic position, and at the same time, it must use high-speed, large-capacity communication technology to transmit the train's position in real time. Information, so as to allow the dispatching center personnel to accurately grasp the operation of the train, so as to direct the operation of the train and ensure the safety of the train. To complete this difficult task, "Beidou" navigation and 5G technology are inseparable.
The ascendant 5G communication technology is not only an indispensable infrastructure in the intelligent era, but also a landmark technology in the intelligent era. It has high bandwidth, high speed, large capacity, low power consumption, low latency, interconnection of everything, and information perceivable. Regulation is its distinctive advantage and feature, which can meet the future application needs of virtual reality, intelligent manufacturing, and autonomous driving.
The "Beidou" satellite navigation system is a global, high-precision time-space reference independently developed by my country. Its biggest advantage lies in the global positioning of the system, which enables precise synchronization of global time. The combination of "Beidou" and 5G to form an "air-space-ground" integrated network system can produce unparalleled five intelligences: perception, learning, cognition, decision-making and regulation.
The train control system based on "Beidou" satellite positioning can continuously and accurately obtain train position information, changing the traditional train control tracking interval method based on fixed automatic blocking technology, and by adopting the tracking interval method of mobile blocking, the tracking interval of trains is greatly increased. Reduce, thereby improving transportation efficiency. Through the "Beidou" satellite, it is also possible to locate the front and rear of the same train, so as to carry out the integrity check of the train to prevent the disintegration of the train and bring safety risks to the following trains.
"Beidou" and 5G technology complement each other. "Beidou" can give 5G technology the ability to sense time and location globally, stimulate the powerful kinetic energy of mobile communication networks and the Internet, and can instantaneously locate mobile information such as high-speed rail trains, determine its destination and instantaneous speed, and satisfy High-speed trains have technical requirements for mobile blocking.
According to the goals set out in the "Outline of the Advanced Railway Planning for a Powerful Country in the New Era", by 2035, China's high-speed trains will have a "super brain" that uses Beidou satellite navigation system and 5G communication technology to form an air-space-ground integration-a new generation of more efficient , A smarter and more environmentally friendly train control system, the train tracking interval is shortened from the current shortest 3 minutes to about 2 minutes, the line transportation capacity is increased by more than 30%, and the per capita energy consumption per 100 kilometers can be reduced by about 30%.
Further reading
The development of high-speed train control technology in various countries
Over the years, Europe has developed a European Train Operation Control System (ETCS) suitable for the local area. The ETCS-2 level train control system uses the traffic permit generated by the wireless block center on the ground, provides the train positioning reference through the fixed transponder, and uses GSM-R The wireless network realizes "car-ground" two-way information transmission, and it has been widely used in Europe.
Since 2013, Europe has started the research and development of a new generation of train control system (NGTCS), among which the innovative project "Modern Traffic Management and Control System" proposed "mobile block, the highest level of unmanned driving, train safety positioning (satellite technology) ), on-board equipment integration, intelligent signal system, train virtual connection" and other technological development directions.
The active train control system (PTC) in the United States is also very powerful, with functions such as train overspeed protection, train collision prevention, and safety of trackside workers. According to the GPS positioning system, the train obtains its own location, and sends the train location to the PTC server through the wireless communication network. The PTC server can calculate the train parking location based on the obtained information and send the location information to the on-board equipment. The PTC system has a dispatch center, which can intervene in the operation of trains to prevent train collisions.
The East Japan Railway Company developed the ATACS system using mobile block technology. This system is mainly composed of radio devices, base devices, command devices and vehicle-mounted devices. The traditional train control system is mainly completed by ground equipment, while in the ATACS system, the control of the train is completed by the ground and the vehicle.
It can be seen from the above that countries and regions with developed high-speed rail such as Europe, America and Japan have also been committed to the research of "mobile blocking" technology.
In order to meet the needs of high-speed railway construction and development, my country's high-speed railway train control technology draws on the successful experience of European ETCS, and has made a huge leap from scratch. The my country Train Operation Control System (CTCS) independently developed by our country is divided into 5 levels, from CTCS-0 to CTCS-4, with different scope of application. The CTCS-3 system is mainly used for high-speed railways with speeds above 300 kilometers per hour in my country, which is an advanced train control system developed based on wireless communication, track circuits and fixed automatic blocking.
The CTCS-4 system is a new generation train control system based on mobile block, Beidou navigation and 5G communication technology in China for 2035. It is known as the "super brain" of trains. This is a milestone major progress in China's high-speed train control technology. .