Core Insights - The article highlights the significance of railway construction in Northeast China, particularly focusing on the challenges posed by permafrost and extreme weather conditions, and the innovative techniques employed to address these issues [1][5]. Group 1: Railway Construction Challenges - The Harbin-Yichun High-Speed Railway (Ha-I High-Speed Railway) is the northernmost high-speed railway under construction in China, designed to traverse areas with permafrost, where temperatures can drop to as low as -40°C [5]. - The construction of railways in permafrost regions faces two major challenges: frost heave and thaw settlement, which can lead to significant structural issues [9]. Group 2: Role of Engineering Testers - Engineering testers play a crucial role in ensuring the quality of railway projects, responsible for geological surveys and comprehensive quality control throughout the construction process, earning them the title of "railway guardians" [5][9]. - The work of engineering testers involves not only physical labor in challenging environments but also requires advanced professional knowledge to assess soil conditions and determine appropriate construction materials [9]. Group 3: Innovative Techniques - Concrete rebound testing is utilized to estimate the strength of concrete by measuring the rebound distance of a hammer after striking the surface, which serves as an indicator related to its strength [7]. - After extensive testing, results can guide workers in selecting the type of fill material for the roadbed based on the moisture content of the permafrost, ensuring the durability and quality of the high-speed railway [9].