Core Viewpoint - The article highlights the critical role of 5G technology in ensuring reliable communication for high-speed trains operating in the West Extension High-Speed Railway, particularly in tunnel environments where signal integrity is essential for safety and passenger experience [1]. Group 1: Maintenance Operations - The maintenance team, led by Ma Jinjing, undertook urgent repair tasks at the Yijun Tunnel, addressing issues such as a cable leak and signal attenuation [1][3]. - The team successfully identified and fixed a faulty cable joint that was causing abnormal signal reflection, completing the task within a tight four-hour window [3][5]. Group 2: Technical Innovations - The West Extension High-Speed Railway employs a new "leak cable introduction" technique, which relocates critical cable joints to cable trenches, reducing the risk of equipment falling off and facilitating easier maintenance [4]. - The installation of leak cables is designed to ensure seamless signal coverage by strategically placing them at heights corresponding to train windows and roofs, effectively creating a "signal corridor" [5][6]. Group 3: Performance and Reliability - The newly repaired cable joint achieved a reflection coefficient of 1.1, which is better than the standard of 1.5, ensuring stable wireless communication between train and ground control systems [5]. - The railway's design incorporates advanced anchoring techniques to withstand the extreme conditions created by high-speed trains, ensuring the durability of the communication infrastructure [6].

Core Viewpoint - The Xi'an to Yan'an high-speed railway has achieved full coverage of public 5G signals, even in tunnels, enhancing passenger connectivity and experience during travel [2][6]. Group 1: High-Speed Railway Overview - The Xi'an to Yan'an high-speed railway, the first in the Shaanxi Northern Revolutionary Area, successfully transported 97,000 passengers over the New Year's holiday [2]. - The railway features a significant proportion of tunnels, with over 55% of its length consisting of tunnel sections [2]. Group 2: 5G Signal Coverage - The railway's construction included the simultaneous installation of infrastructure to ensure full public 5G signal coverage, even in tunnels [2]. - The New Yan'an Tunnel, which is 16 kilometers long, has over 80 chambers, with 16 designated for base station installations, ensuring one base station per kilometer [2][3]. Group 3: Technical Innovations - The use of leaky coaxial cables, which have periodic openings in their outer skin, allows for uniform signal radiation throughout the tunnel, creating a continuous "signal corridor" [3]. - The installation of leaky cables is designed to align with the height of train windows, optimizing signal coverage within the train [3]. Group 4: Engineering Challenges and Solutions - The design team faced significant challenges due to the aerodynamic effects created by high-speed trains, which required precise calculations for the installation of leaky cable supports [3][4]. - A new type of mechanical anchor bolt was developed, which has a tensile load capacity of 15 kilonewtons, significantly exceeding the required strength for installation [4]. Group 5: Testing and Implementation - A full-scale simulation communication room was constructed to replicate the typical equipment configuration of the railway, allowing for extensive testing under various extreme conditions [4][5]. - The final installation process involved meticulous steps to ensure precision, including controlling drilling depth and using specialized equipment to prevent contamination [5]. Group 6: Future Applications - The successful implementation of 5G coverage on the Xi'an to Yan'an railway has led to the development of over 190 construction standards, which will be applied to other ongoing projects such as the Xikang and Xishi high-speed railways [6].