China's fixed-asset investment in railways was 850.6 billion yuan (about 117 billion U.S. dollars) in 2024, up 11.3 percent from the previous year, according to data released by the China State Railway Group Co., Ltd.
In 2024, a total of 3,113 kilometers of new railway lines were commissioned, of which 2,457 kilometers were high-speed railways.
By the end of 2024, China's railway operating mileage reached 162,000 kilometers, of which 48,000 kilometers are high-speed railways, marking a record achievement, according to China Railway.
Efforts focused on the construction of over 100 major railway projects, as well as projects for implementing major national strategies and building security capacity in key areas. Key projects included the commencement of constructing 17 new high-speed rail sections, such as the Yichang-Fuling line in southwest China's Chongqing Municipality.
Meanwhile, 42 projects were completed and opened to traffic. Additionally, feasibility studies for 20 new projects, including the Jiamusi-Tongjiang railway expansion in northeast China's Heilongjiang Province, were approved, paving the way for future development.
The year also saw significant progress in freight infrastructure. A total of 44 dedicated railway lines and 12 logistics bases were completed, further enhancing the sector's capacity to support economic growth.
China's fixed-asset investment in railways hits 117 billion USD in 2024
Researchers from the University of Science and Technology of China have achieved a major breakthrough in optical clock technology, developing a strontium optical lattice clock with stability and uncertainty both surpassing the 10⁻¹⁹ level, meaning the clock would lose or gain less than one second over roughly 30 billion years.
The findings were published in the international metrology journal Metrologia on Thursday.
Optical clocks are considered the most precise timekeeping devices currently available. They measure time by using the frequency of light emitted when electrons transition between energy levels in atoms. They can directly support the redefinition of the second in the International System of Units.
"This breakthrough enables China to rank among the top in the world in the development of optical clocks. It also provides a feasible technical path for the development of transportable optical clocks and satellite-borne optical clocks, and lays a solid and reliable foundation for using optical clock technology in areas such as testing fundamental laws of physics, supporting next-generation satellite navigation systems, and establishing a globally unified ultra-high-precision time reference," said Dai Hanning, professor of the university.
Beyond time-keeping, optical clocks can provide highly accurate time references for modern technologies such as satellite navigation, telecommunications and precision measurements. They also offer new experimental platforms for testing fundamental physics, including general relativity, as well as for the detection of gravitational waves and dark matter.
Achieving both stability and uncertainty at the 10⁻¹⁹ level opens the door to a range of frontier applications. These include millimeter-level measurements of gravitational potential and altitude, which could help monitor crustal deformation, groundwater changes and volcanic activity, as well as improve geoid mapping for disaster prevention and resource exploration.
Chinese optical clock accurate to within 1 second over 30 bln years
Chinese researchers develop world's most precise optical clock
