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High-speed rail (HSR) is a form of rail transportation that utilizes specialized rolling stock (i.e., all of the component vehicles of a train, like the locomotive and passenger carriages) and track systems to run at substantially greater speeds than traditional rail systems. One definition designates existing lines running at speeds exceeding 200 kph (120 mph) as HSR, as well as new lines running over 250 kph (160 mph).
High-speed rail in the current sense of the term got its start in 1964 with the Japanese Shinkansen (“new trunk line”), often referred to as the “bullet train.” The Shinkansen initially ran at speeds of 210 kph (130 mph). Japan’s Shinkansen was a breakthrough development in passenger rail transport, paving the way for similar systems now operational in Europe, China, South Korea, Russia, Turkey, and a number of other countries.
As opposed to more exotic technologies like maglev or hyperloop, high-speed rail resembles traditional rail in that it uses continuously welded tracks as a guiding system, typically of the 1,435 mm standard gauge. However, HSR lines need distinct ground infrastructure to operate, and are not usually integrated with other rail lines. This makes HSR systems costly to build and operate. The vast majority of HSR lines are designed for passenger transport.
In the countries where it exists, HSR competes with air transport to traverse long distances. Speeds are significantly slower than commercial aircraft, but by sharing stops and stations with existing local transit, HSR can cut travel times on shorter regional trips by eliminating the need to travel to and wait at airports often located far from urban cores.
Japan’s L0 Series Maglev is the fastest train in the world, with a speed record of 374 mph or 602 km/h. It could go the distance from New York City to Montreal in less than an hour. Today, an integrated HSR network crisscrosses Europe, made possible in part by European Union law and funding. France’s TGV POS and Italy’s Frecciarossa 1000 reached speeds of 357 mph (575 km/h) and 245 mph (394 km/h) respectively.
The first high-speed railway corridor of length 508 km is currently under construction between Mumbai and Ahmedabad at a top operational speed of 320 km/h (200 mph) along the western coast. The corridor will use Standard gauge line and will be built with Shinkansen technology. It is expected to carry passengers between the two cities in just three hours and the ticket prices are expected to be cheaper than aeroplanes i.e. ₹2,500 – ₹3,000.
China has half of the eight fastest trains, and the world’s largest high-speed railway network. In recent years, China has emerged as the world’s undisputed HSR leader in terms of the length of lines constructed. It has built over 27,000 kilometers (16,777 miles) of track since it began HSR construction in 2008, and has set a goal of 38,000 km (23,600 miles) by 2025. By comparison, other leaders like Japan, France, Germany, and Spain have each built around 3,000 kilometers (1,680 miles) of HSR.
Bullet trains in China can run as fast as 350 kilometres per hour and Chinese researchers want them to take the top speed of 450km/h.
China wants even faster bullet trains, and a team of scientists in the southwest of the country have suggested a way to do it: add wings. Their study found that adding five pairs of small wings on each train carriage would generate additional lift and reduce the train’s weight by nearly a third, taking the top speed to 450 kilometres per hour.
The research is part of a project launched by Beijing earlier this year named CR450, which aims to develop a new generation of high-speed trains that can travel at that speed.
In a new development, Chinese researchers have claimed to have developed the most sophisticated wind detection laser in the world, which might be used to monitor air pollution, forecast the weather, and accelerate high-speed trains, Hong Kong-based South China Morning Post reported.
The suitcase-sized instrument uses Lidar techniques to detect subtle variations in the wind in remarkable detail. A laser is used to measure the relative movement of air in the atmosphere in a process known as Lidar or Light, Detection, and Ranging.
“Atmospheric wind field detection with meter-level resolution will play a significant role in aerospace safety, high-value target protection, and numerical weather forecasting,” said a statement from the University of Science and Technology of China (USTC) in the eastern province of Anhui.
In 2019, it was revealed that China had started building the world’s most powerful laser radar designed to study the physics of the Earth’s high atmosphere. At the time, it was claimed that it would be used to research atmospheric particles that act as the planet’s first line of defense against dangerous extraterrestrial objects like solar winds and cosmic rays.
Later, in April 2022, China launched the world’s first satellite with laser radar to study carbon dioxide. The unique launch aimed to improve global carbon and air pollution monitoring capacity and realize the leapfrog development of China’s atmospheric remote sensing technology. However, the current development of a laser radar for wind detection is significant in its own right. US-based defense contractor Raytheon developed the first-ever laser radar for wind detection in 1970.
Professor Dou Xiankang from USTC was in charge of the study. According to the announcement by Dou and his team, the new laser radar’s sensitivity has outperformed the existing technology by two orders of magnitude in terms of sensitivity.
Light Detection and Ranging is a remote sensing method that uses light as a pulsed laser to measure ranges (variable distances) to the Earth. Doppler wind Lidar (DWL), extensively used in engineering and scientific studies, uses the Optical Doppler effect to determine atmospheric wind speed with high spatial-temporal resolution and extended detection range. The Doppler Lidar works by transmitting short pulses of infrared laser light into the atmosphere.
However, China’s new laser radar development might make China’s high-speed trains faster and safer, according to the researchers, who claimed that the device had let them spot peculiar high-speed train turbulence that had never been seen before. The radar development became even more significant after a bullet train in China suffered a crash.
They began by monitoring the system using an anemometer, a tool for measuring wind speed, which was highly accurate, according to the researchers. The team’s hyperfine PCDWL technology successfully measured wind speed to within 0.5 meters per second during a test on the USTC campus.
After that, Dou’s team conducted a second experiment at a high-speed train station in Suzhou, Anhui province. The PCDWL equipment continuously captured photographs of the high-speed wake created by bullet trains passing 350 kilometers/hour for more than 100 hours (217.5 miles per hour). The observation, which attained previously unheard-of three meters and 0.1-second resolutions, showed spinning vortexes with recurrent patterns called “Von Karman vortex shedding.”
According to computer modeling, these vortexes can be formed near the tail of a high-speed train, but no one has ever observed one in action. According to the researchers, the discovery may improve high-speed maglev trains’ stability, effectiveness, and safety. A 600 kilometers/hour maglev train, which is almost twice as fast as the existing limit, is being developed in China. It was revealed as part of a five-year plan for innovation under railway science and technology by the National Railway Administration (NRA).
Rail transport for Military
China’s rapidly developing high-speed train network spanning the length and breadth of the giant nation could prove to be of “immense strategic military value” for the rapid movement of forces and missiles, an official media report said. China’s high-speed rail lines are becoming a major transport force for the People’s Liberation Army (PLA), allowing the rapid movement of military forces throughout the country, a recent state-run news report revealed.
“A lightly equipped division could be moved on the Wuhan-to-Guangzhou line about 600 miles (965 kms) in five hours, a fairly rapid mobilisation in military terms,” the China Youth Daily said outlining military benefits of the country’s six high-speed rail lines.
The report says that China’s high-speed rail network will provide “immense strategic military value”. “And the Second Artillery (missile forces) could use the high-speed rail network to quickly deploy short-range missiles ‘in a certain strategic direction’, presumably from inland locations to coastal regions near Taiwan or Japan,” the Washington Times quoted the Daily’s report as saying.
References and Resources also include:
https://www.planetizen.com/definition/high-speed-rail
https://eurasiantimes.com/chinas-bullet-trains-could-fly-scientists-say-new-radars-can-detect-wind/
