94Ha ViewpointWhy can China’s high-speed trains run so fast and still be so stable? Even a coin won’t fall over when placed on them? The front of the train adopts a streamlined design, the axle box of the high-speed EMU bogie is elastically positioned, the line is straightened and smoothed, and differential settlement is strictly controlled… Let’s explore the hard-core technology hidden in this “great national weapon”!
The secret of being fast and stable
1. Front and body design
The streamlined front and increased slenderness ratio design are adopted. For example, the “head shape” of Fuxing CR400BF is about 2 meters longer than that of Harmony, and the overall shape is more streamlined, which reduces the running resistance by 12%, increases the speed and reduces energy consumption.
Guides are set on both sides of the front to guide the airflow to generate downward pressure, prevent the front of the car from “floating” when driving at high speed, and ensure the smooth operation of the train.
2. Bogie technology
The bogie is called the “speedster” of high-speed EMUs. It adopts technologies such as axle box elastic positioning, air springs, axle box springs, various shock absorbers, and curved wheel treads to avoid instability of the vehicle when running at high speed.
The critical instability speed of the bogie of my country’s high-speed EMU can reach more than 500 kilometers per hour, providing high safety redundancy for the safe operation of high-speed rail.
3. Track system
Ballastless track is adopted, which is composed of 500 meters long rails connected seamlessly. The straightness of the guide surface of the rail top running surface of the welded joint is controlled at 0.2 mm to ensure the smoothness of the track.
The track laying accuracy requirements are extremely high, such as the track height and track deviation value of 2 mm, the track horizontal deviation value of 1 mm, and the track gauge deviation value of plus or minus 1 mm.
The roadbed differential settlement standard is extremely strict, only 5 mm, to ensure the long-term stability of the track.
4. Power system
The high-speed rail is composed of multiple EMUs, each of which has power and sufficient power to increase the speed.
High-power traction power is adopted to meet the dynamic indicators such as the maximum speed, acceleration performance and climbing ability of the train.
5. Line planning and maintenance
The line planning is as straight as possible, reducing curves, and the curve radius is designed to be larger than that of conventional railways to ensure safe and fast turning of high-speed railways.
In daily operations, rail grinding vehicles are used to maintain and grind the tracks to ensure that the tracks are always in the best condition.
2. Reasons for fast and stable operation
1. Technological innovation and accumulation
After years of technical research and experience accumulation, China’s high-speed rail has made major breakthroughs in head design, bogie technology, track system, etc.
Continuously introduce, digest, absorb and innovate, forming a high-speed rail technology system with independent intellectual property rights.
2. Strict standards and specifications
During the construction, operation and maintenance of high-speed rail, strict standards and specifications have been formulated to ensure that every link meets high-quality requirements.
There are clear regulations and detection methods for track laying accuracy, differential settlement of roadbed, quality of welded joints, etc.
3. Optimization of comprehensive system
High-speed rail is a huge system project, including infrastructure, fixed equipment, mobile equipment, safety assurance system and transportation organization methods.
By optimizing the coordination between various subsystems, the high-speed rail is able to run fast and stably.
