As prototypes of China's CR450 bullet train, the world's fastest high-speed train, are now undergoing type testing, a quiet yet critical achievement has been made behind the scenes.
At the heart of this technological leap is Zhang Hongbin, a senior technician at Tieke Zongheng (Tianjin), a subsidiary of the China Academy of Railway Sciences Group Co., Ltd. His mastery of machining is helping redefine the limits of precision and performance in train braking systems.
The CR450 must decelerate from 400 km/h to a full stop in just 112 seconds over 6,500 meters. Achieving this requires an exceptionally reliable brake system, particularly the brake disc hub, a key component that Zhang specializes in crafting.
Back in 2012, during the development of the now-iconic "Fuxing" bullet train, a bottleneck emerged: conventional methods required importing high-precision grinders and long lead times. Zhang, at age 26, proposed an ambitious alternative -- achieving grinder-level precision using a lathe.
"There were voices of doubt. They didn't believe a lathe could match the accuracy of a grinder. But there is an old saying: a newborn calf is not afraid of a tiger," said Zhang.
The challenge was immense. The brake hub demanded a precision tolerance of just 0.005 millimeters -- about one-sixteenth the thickness of a human hair.
Zhang often spent hours at the lathe, tuning cutting paths, adjusting speeds, and even listening to the machine's sounds to detect minute changes in its behavior.
"If I listen carefully, I can judge the vibration of the part and whether the cutting tip is worn. It feels like I'm communicating with the machine," said Zhang.
Over more than three months, Zhang and his team tested seven tool structures and altered nine cutting paths.
Their persistence paid off: they not only cracked the technical challenge of machining the hub on a lathe, but also eliminated an entire production step and doubled the efficiency compared to foreign grinding techniques.
From catching up to taking the lead, China's high-speed train has kept setting new records through self-reliance and innovation. Thanks to craftspeople like Zhang, the precision at the core of this progress has also kept pushing new boundaries.
Precision craftsman refines brake hub for world's fastest high-speed train
Russia said on Wednesday that its armed forces gained control over a settlement in Zaporizhzhia region in southeastern Ukraine, while Ukraine said on the same day that its armed forces attacked multiple Russian strategic infrastructure.
The Russian Ministry of Defense said in its latest report that Russian forces brought under controlled the Zarechnoye Settlement in Zaporizhzhia Region and attacked Ukrainian troops in the direction of Sumy and Kharkiv in northeastern Ukraine over the past 24 hours.
The ministry also said that over the past day, Russian forces struck Ukrainian military-industrial enterprises, energy facilities, transportation infrastructure, and temporary deployment points of Ukrainian troops and foreign mercenaries across 147 locations.
Meanwhile, the General Staff of the Armed Forces of Ukraine said in a war report released on Wednesday that Ukrainian forces attacked multiple Russian targets earlier on the day.
The report said that a synthetic rubber plant, which was located in the Russian city of Yefremov in the Tula Region and was used to produce components for plastic explosives and key raw materials for solid rocket fuel, was attacked.
It also reported that the Ukrainian forces struck a Russian base for unmanned vessel storage and maintenance in Crimea.
Russia's Federal Security Service (FSB) said on the same day that Russian forces thwarted a planned sabotage and terrorist attack targeting critical infrastructure in the Tyumen Region.
According to the FSB, the suspect acted on orders from Ukrainian special services and planned an attack on a dispatch station of a major oil pipeline operated by the Russian company Transneft.
The individual attempted to extract components he had bought from a cache to assemble an improvised explosive device earlier on the day. When security personnel tried to capture him, he offered armed resistance and was eventually neutralized, the FSB said.
Also on Wednesday, Ihor Terekhov, mayor of Kharkiv, said that a thermal power plant on the outskirts of the city was attacked by Russian forces on the day, resulting in one death and 13 injuries so far.
Additionally, the attack has directly impacted local heating supply and public transportation operations.
Russia claims controlling new settlement, Ukraine reports striking Russian strategic infrastructure
