Chiang rai: The cause of the Doi Luang tunnel wall collapse, which resulted in the death of two workers and injured two others, has been revealed by engineers working on the site. According to Thai News Agency, Mr. Chucheep Pongchai, Governor of Chiang Rai Province, and Mr. Jitakorn Thiwongwiang, District Chief of Doi Luang, conducted an inspection at the scene of the incident. The collapse occurred last night when lighting equipment under construction fell, leading to the casualties. The injured individuals have been evacuated and are receiving medical treatment at a local hospital. Mr. Pattapong Boonkaew, the project engineer, explained that the incident took place at 4:30 PM within the Doi Luang Tunnel, which is part of a larger project comprising four tunnels. The Doi Luang Tunnel, specifically, spans 3.4 kilometers. The collapse happened in a section where the walls were undergoing protection work amid heavy rainfall, which is common in the area and can weaken exposed sections. Temporary structural su pport is currently in place. Mr. Boonkaew assured that once the protection and drainage systems are finalized, the risk of similar incidents will be minimized. Construction activities are set to resume after a thorough geological assessment. He emphasized that the tunnel is structurally sound, having previously withstood three earthquakes, and the incident does not affect the overall project timeline or safety. Governor Pongchai reported the incident to high-level officials, including the Director-General of the Department of Disaster Prevention and Mitigation and the Prime Minister, who has expressed concern and instructed immediate inspection of the area. The provincial disaster prevention center is actively monitoring water management systems to prevent any further incidents. Engineering analyses will be essential to address the challenges posed by the area's rainfall, but the construction will proceed as planned. The Doi Luang Tunnel is part of an extensive railway project covering 323.1 kilometers from Den Chai District, Phrae Province, to Chiang Khong District, Chiang Rai Province. The project includes other tunnels such as the Ngao Tunnel in Lampang Province, which is the longest in the country, the Song Tunnel in Phrae Province, and the Mae Ka Tunnel in Phayao Province. The entire railway line is anticipated to be operational by January 2028, with construction currently 64% complete, slightly behind the projected schedule.