The six speed increases from 1997 to 2007 have enabled China to enter the era of high-grade ordinary railways (especially high-speed trains with a speed of 160) and high-speed railways (high-speed trains with a speed of 160 or more run multiple units), and explored the technology of high-speed railways in China. 1 April, 9971First speed increase. Express trains and night trains in a narrow sense were introduced for the first time. The top speed of Beijing-Guangzhou, Beijing-Shanghai and Beijing-Harbin is 140 km. The average speed of passenger cars in China increased from 65438+48km at the beginning of 0993 to 54.9km.. 1 998101,the second speed increase, the maximum speed of generalized express trains reached 160 km, and the maximum speed of express trains in non-speed-increasing sections reached 120 km, which improved the grade of ordinary railways. 2000 10, 2 1, the third large-scale speed increase, the speed increase line is close to 1 10,000 kilometers, and the average speed of passenger cars reaches 60.3 kilometers per hour. There are seven columns and three columns for horizontal modulation. Expanded the scope of middle and high-grade ordinary railways. 200 1, 1, 2 1, the fourth large-scale speed increase, the speed-up line increased by 3000 kilometers. At 00: 00 on April 8, 2004, the fifth large-scale speed increase, the speed-up line increased by 3500 kilometers, and the 19 direct express train was added, with a maximum speed of 160 kilometers per hour. When the line foundations of some sections of several main trunk lines meet the requirements of 200 kilometers per hour, they will be upgraded to intermediate high-speed railways, foreign EMUs will be introduced, and the freight car system will be greatly reformed. At 0: 00 on April 18, 2007, China Railway increased its speed for the sixth time, and the speed of 2 12 pairs of intercity railway EMUs exceeded 200 kilometers per hour. The CRH of China brand high-speed railway appeared, forming a number of fast passenger passages and further developing the fast railway. Moreover, the maximum speed of the existing line is 250km/h, and it has reached the gate of China high-speed railway. Nine core technological breakthroughs have been made in the construction of high-speed railway, which provides conditions for the next development of high-speed railway. On August 2008 1, China opened the first high-speed rail, namely the Beijing-Tianjin Intercity, and entered the era of express rail-high-speed rail.