Workers Begin Clearing Chiang Rai Railway Tunnel After Deadly Collapse

Last updated: June 22, 2026 5:27 am

3 hours ago

CHIANG RAI – On June 21, authorities began clearing the Doi Luang railway tunnel following a tragic construction accident. A sudden rock collapse on the evening of June 20 claimed the lives of two workers and severely injured two others. The incident occurred at the major construction site of the Den Chai-Chiang Rai-Chiang Khong railway project.

Officials from the State Railway of Thailand (SRT) and the CKST-DC3 Joint Venture quickly secured the immediate area. Geologists and expert engineers are now assessing the tunnel to ensure safe working conditions. They plan to install stronger protective walls to prevent any future disasters from occurring.

Key Takeaways

Fatal Accident: Two construction workers died, and two were injured in a sudden rock collapse on June 20.
Location: The incident happened inside the 3.4-kilometer Doi Luang tunnel in Chiang Rai, Thailand.
Main Cause: Heavy rainfall over the past year severely weakened the unprotected earth tunnel walls.
Next Steps: Engineers are improving safety measures, and police are actively investigating the work site.

The tragic accident resulted in the sudden loss of two young construction workers. Police identified the deceased as Mr. Aphidet Kaewpraken, 24, from Kanchanaburi, and Mr. Tu Tu Hun, 29, from Myanmar. Two other workers suffered serious injuries and are receiving urgent medical care.

Ms. Supamas Khaewsawai, 28, also from Kanchanaburi, and Mr. Tun Tun Win from Myanmar survived the sudden collapse. They are currently being treated by specialists at the Chiang Rai Prachanukroh Hospital. Local police, led by Pol. Col. Annop Lertsuwan, immediately launched a joint investigation with project engineers.

Investigators found that the workers were standing on tall steel scaffolding at the time. They were drilling and attaching steel supports directly to the excavated earth wall. Suddenly, heavy rocks broke loose from the wall and tragically crushed the workers below.

Workers Begin Clearing Chiang Rai Railway Tunnel

Project Engineers Investigate

Project engineers shared important insights into what caused the sudden tunnel collapse. They explained that the main tunnel excavation was actually completed early last year. However, the site absorbed massive amounts of heavy rainfall for a full year before full protection was installed.

This water buildup severely weakened the earth and caused unpredictable, dangerous geological shifts. If the full protection systems had been in place, engineers claim this tragedy would not have happened. Moving forward, the project will implement strict safety protocols before reopening to workers.

Chiang Rai Governor Chucheep Pongchai quickly responded to the developing crisis. He ordered the project team to use vital data from the Provincial Disaster Prevention and Mitigation Office. They must combine ongoing rainfall data with geological tests to guarantee total safety.

Governor Chucheep and other local officials also visited the injured workers at the local hospital. They offered emotional support and promised a thorough review of all current safety standards. This massive public infrastructure project remains highly important for the entire northern region.

The Den Chai-Chiang Rai-Chiang Khong railway was approved by the Thai cabinet in July 2018. It has a massive budget of 85.345 billion baht and spans a total of 323.1 kilometers. Construction officially began in early 2022 and is expected to take seven years to finish.

The third phase covers 87 kilometers from the city of Chiang Rai to Chiang Khong. The Doi Luang tunnel is one of four major tunnels, measuring 3.4 kilometers long. Despite the recent accident, the project boasts a completion rate of 72.12%, running 9.21% ahead of schedule.