Core Viewpoint - The Qingdao Metro construction is making significant progress with multiple key milestones achieved across various lines, enhancing the city's rail transit network efficiency and connectivity. Group 1: Line 2 - The second phase of Line 2 has successfully completed the structural topping of the East Chuan Road Station, which connects the eastern urban area with Laoshan, improving transit coverage in the region [2]. Group 2: Line 5 - The main structure of the Funing Interchange Station on Line 5 has been successfully poured, and the "Haihu" section has achieved double-line completion 15 days ahead of schedule, overcoming complex geological conditions [3]. Group 3: Line 7 - The assembly of the first prefabricated track top wind duct in Qingdao Metro has been completed, significantly reducing construction time and minimizing on-site dust and noise [4]. Group 4: Line 15 - Line 15 has made critical advancements with the completion of the main structure at the Jingcheng Road Station and the successful tunneling of the "Xiafu" section, enhancing connectivity between key urban areas [5]. - Currently, the total length of the under-construction lines exceeds 100 kilometers, with over 20 key milestones achieved this year [5].

Group 1: Metro Line 2 Phase II - The main structure of Longchuan Road Station has successfully topped out, achieving multiple records and completing the main structure 20 days ahead of schedule [3] - The station is part of the 8.9 km underground Line 2 Phase II, which connects the eastern part of Licang District with the city center and is expected to enhance transportation convenience for residents [3] Group 2: Metro Line 5 - The construction of the section between Changle Road Station and Eight Number Pier Station has achieved a breakthrough in shield tunneling technology under complex geological conditions, with a settlement control precision of 0.54 mm [5] - The completion of the protective pile construction at Lake Island Station has laid a solid foundation for subsequent excavation and structural work, finishing 69 days ahead of schedule [5] Group 3: Metro Line 7 - The main structure of all 7 stations in the second phase of Line 7 has been topped out, marking significant progress and multiple firsts in the construction timeline [6] - This line will facilitate rapid north-south connectivity, enhancing urban rail transit and boosting economic development along the route [6] Group 4: Metro Line 9 - The successful tunneling of the "Yongxing No. 1" shield machine under the墨水河 marks a record for the longest waterway crossing (130 meters) in the construction of Qingdao Metro Phase III [7] - The first phase of Line 9 is a key east-west backbone line in northern Qingdao, with a total length of 16.63 km and 13 stations planned [7]