Yesterday (April 17), train tickets for the first day of the May Day holiday (May 1) went on sale.
During the holiday travel season, taking the high-speed rail bullet train has become a travel choice for many people. From 200 kilometers per hour to 300 kilometers per hour, and then to the current speed of 350 kilometers per hour, China's high-speed rail is running faster and faster, and it also brings more convenience to people's travel.
According to the latest news, the CR450 EMU prototype is planned to roll off the assembly line this year, and the operating speed will be increased from 350 kilometers per hour to 400 kilometers per hour. What does it mean, why is it necessary, and is it feasible?
Why speed up?
Since September 2017, the Fuxing China Standard EMU CR400 train has been put into operation on the Beijing-Shanghai high-speed railway, creating a new benchmark for the world's high-speed rail operation speed with a speed of 350 kilometers per hour. Today, the CR450 EMU with a speed of 400 kilometers per hour is being developed intensively.
According to the naming convention of China's high-speed railway (CR is the abbreviation of China Railway, that is, China Railway, and the following numbers indicate the speed class), CR450 refers to a high-speed EMU train with an experimental operating speed of 450 kilometers and a commercial operating speed of 400 kilometers.
From 350 kilometers per hour to 400 kilometers per hour, the speed of high-speed rail is of great significance.
On the one hand, this is the result of the continuous improvement of the technical ability and level of the mainland railway, and it also enables the mainland high-speed railway to maintain a leading edge in the world.
According to the person in charge of the Ministry of Science and Technology and Information Technology of China Railway Group, the "CR450 Science and Technology Innovation Project" is a major scientific research project determined by the national "14th Five-Year Plan". The "CR450 Science and Technology Innovation Project" mainly includes CR450 EMUs and high-speed rail lines, bridges, tunnels and other infrastructure technology innovations at a speed of 400 kilometers per hour.
The CR450 EMU, which will be rolled off the assembly line within the year, will promote the technological innovation of high-speed railway EMUs and infrastructure systems in mainland China, and fill the gap in the technical standard system of high-speed rail with a speed of 400 kilometers per hour. The relevant scientific research results obtained by the CR450 scientific and technological innovation project will be widely used in the field of railway construction and operation, further enhance the self-reliance and self-improvement ability of railway science and technology, and consolidate and expand the world's leading advantage of mainland high-speed rail technology.
Today, China's high-speed rail has formed the world's largest operating network, with a domestic mileage of more than 45,000 kilometers, and the Fuxing has reached 31 provinces, autonomous regions and municipalities, and more than 2.2 billion people have traveled on the Fuxing.
On the other hand, this is the need of economic and social development, which will further reduce the time and space distance between regions and strengthen the connection between cities.
From 350 kilometers per hour to 400 kilometers per hour, the speed is 50 kilometers per hour, which is not only a number, but also a reconstruction of the distance between time and space.
Studies have shown that the best travel distance for EMUs with a speed of more than 200 kilometers per hour is within 800 kilometers, the best travel distance for high-speed trains with a speed of 300 kilometers per hour is about 1,200 kilometers, and the optimal travel distance will be extended to 1,600 kilometers when the speed reaches 400 kilometers per hour.
At present, China's existing high-speed trains can reach speeds of up to 350 kilometers per hour, and if the speed is increased to 400 kilometers per hour in the future, it is possible to reduce the travel time between Beijing and Shanghai from more than four hours to less than four hours.
In addition, the accelerated development of high-speed rail has also promoted the development of related industries. A Fuxing EMU is composed of more than 500,000 parts, covering many technical fields such as machinery, metallurgy, materials, power electronics, and precision instruments.
China Railway Group has taken the lead in establishing a railway science and technology innovation alliance covering key enterprises, universities and scientific research units inside and outside the railway industry to achieve deep integration of production, education and research. From R&D, manufacturing, to the coordinated development of the whole chain of operation and maintenance services, 260 independent technical systems have been formed, and more than 100 core enterprises and more than 2,100 affiliated enterprises have designed and produced EMU parts, covering more than 20 provinces, autonomous regions and municipalities in China.
The speed is 350 kilometers per hour→ 400 kilometers per hour
Is it feasible?
The acceleration of high-speed rail is not a simple acceleration process, and involves many considerations.
First of all, run fast. The key to making the train run fast is to make it more "physical" and "lighter".
In terms of "physical strength", Zhao Hongwei, chief researcher of the China Academy of Railway Sciences, said that in order to reach a speed of 400 kilometers per hour, it is necessary to increase the power. The traction power of the CR400 is 9,600 kW, and on the CR450 it reaches 11,000 kW.
The permanent magnet motor of the CR450 traction system is the first time that it has been applied to a high-speed rail train in commercial operation in mainland China. In the working state, it is charged at more than 2,000 volts, the number of revolutions per second is 100 revolutions, and the power is increased by 14.5%.
In terms of "weight", the CR450 uses new materials such as magnesium alloy and carbon fiber, and the "weight" when fully loaded with passengers has dropped from more than 500 tons to more than 460 tons.
Second, stop steadily. Zhao Hongwei believes that from a speed of 350 kilometers per hour to a speed of 400 kilometers per hour, the most critical technology is not whether it can run, but whether it can stop, stop steadily, and stop accurately.
At speeds of up to 400 km/h, the energy generated by an emergency stop can boil 6.8 tonnes of water from freezing to boiling point in two minutes. With so much energy, can the train stop safely?
The red disc rotating at high speed in the picture below is testing the matching degree of the brake pads and the brake disc to see if the brake system is reliable. The red-hot disc is constantly collecting data, and the train's intelligent system is precisely calculating the best way to start, speed up, and stop.
Zhao Hongwei said: "The most important thing is the braking system, which must be able to stop. Our technical indicators at the top level require that the braking distance should be consistent with the braking distance of the CR400 at a speed of 350 kilometers per hour, and it is also 6500 meters, so the braking capacity of the entire train must be improved. ”
Finally, low energy consumption. Increasing speed means increasing energy consumption, how to reduce energy consumption?
CR450 EMU uses a large number of carbon fiber composite materials, which have lower density than traditional materials, and have a series of technical index advantages such as light weight, high strength, high temperature resistance, fatigue resistance, etc., which provides an optimal solution for the lightweight of high-speed trains, which is conducive to reducing vehicle weight, speed and energy consumption.
Nie Ying, the overall senior chief designer of the high-speed EMU of CRRC Sifang Co., Ltd., said that like the CR450, the equipment compartment and obstacle remover are made of carbon fiber materials, which can reduce the weight by 30% compared with traditional materials, so that the body is lighter and the energy consumption is lower when running.
Looking at the "report card" of the CR450 through a set of data -
According to the known test data, the weight of the CR450 body is about 10 tons, which is about 12% less than the existing CR400 Fuxing train;
At the same time, the operating resistance and energy consumption indicators are reduced by 20%;
The braking performance and traction efficiency are increased by 20% and 3% respectively, so that the train can achieve an operating speed of 50 kilometers per hour and reach a speed of 400 kilometers per hour under the condition that the braking distance, noise and energy consumption indicators remain unchanged.
In addition, in order to achieve a speed of 400 kilometers per hour, there are requirements not only for trains, but also for high-speed rail lines. The Chengdu-Chongqing Middle Line high-speed railway, which is currently under construction, has a design speed of 350 kilometers per hour, and further speed improvement conditions are reserved in some sections.
Since its launch in 2021, the "CR450 Science and Technology Innovation Project" has successively completed the development of 17 prototypes of new technology components, carried out 57 scientific research tests on the CR400 comprehensive testing train, and created a new record of 453 kilometers per hour for a single train on the open line of EMUs, 891 kilometers per hour for relative rendezvous and 840 kilometers per hour for tunnel rendezvous.
Zhang Dayong, director of the Science and Technology and Information Technology Department of China Railway Group, said that at present, important progress has been made in the technological innovation of railway infrastructure with a speed of 400 kilometers per hour and the construction of a comprehensive test section at a higher speed. The CR450 EMU has completed the formulation of top-level indicators and overall schemes, and has entered the stage of construction design and prototype development, and the prototype will be rolled off the assembly line within the year, and a series of tests will be carried out.
High-speed rail is not only a means of transportation, but also a manifestation of China's scientific and technological innovation capabilities and comprehensive national strength. Perhaps, in the near future, high-speed trains with a speed of 400 kilometers per hour will roar. (News Network)
Source: Beijing Daily client