20 Woosh! World's fastest train

世界上最快的高铁你们知道在哪里吗？就在中国的。本期我就来带大家了解一下世界上最快的高铁（记得点赞关注哦么么哒(ꈍᴗꈍ)ε｀*)）
It is widely known that China has the most ad vanced(先进的) high-speed railway network(网络) in the world. Now, the country is breaking its own speed record with CR450.
CR450 can travel at 400 kilometers per hour on average, with a top speed hitting 453km/h. Before this, the fastest high-speed train operating in a rail network in the world is China's CR400, which runs at 350 km/h on alverage.
Once put into use, for example, the CR450 will shorten the travel time from Beijing to Shanghai to just about two and a half hours, which takes at least four and a half hours at the moment.0“The key is not to make the train run fast but to have it brake(刹车)accirately(精准地) and steadily(平稳地),”Zhao'Hongwei of the China Academy of Railway Sciences told CCTV News. The standard is that the CR450 should have
the same brake distance as the CR400, which is 6,500 meters, even though it travels a lot faster. It can also start braking more quickly, taking just 1.7 seconds compared to the 2.3 seconds needed for the CR400.
The engineers did lots of tests with the brakes to make the system better. In the tests, the brake disc (制动盘) got really hot,
reaching temperatures of up to 700 C. Its color changed from black to red. The changes were then recorded. All the data were saved in a
smart system to make a digital model(数字模型) of the brake system for calculations(计算). Apart from having a better braking system, the CR450 has the same noise level as the CR400. Moreover, it is 12 percent lighter and 20 percent less energy-consuming(耗能的), according to CCTV News. With all its advantages, people are getting excited about the train's debut (首次亮相), which is planned to be within this year.
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