Ngao rail tunnel excavation approaches final stretch in northern Thailand
The 6,215-metre tunnel will serve a railway scheduled to open in 2028, with structural work and systems installation still to follow.
Just 24.30 metres of excavation remain at Ngao Tunnel in Lampang province, with digging expected to finish in December. Measuring 6,215 metres, Thailand’s longest railway tunnel is being built for the Den Chai–Chiang Rai–Chiang Khong railway, where services are scheduled to start in 2028.
A ceremony to mark the breakthrough took place in Ngao district on 11 November, led by Phiphat Ratchakitprakarn, Deputy Prime Minister and Transport Minister. He highlighted the difficulties engineers faced because of the mountainous landscape and complex geology. Excavation started on 22 December 2023.
Anan Phonimdaeng, governor of the State Railway of Thailand, said the differing rock formations demanded specialist construction methods and rigorous safety oversight. Crews encountered limestone as well as volcanic ash deposits hundreds of millions of years old.
Following excavation, construction will move to internal structures and the installation of rail systems and safety equipment. Inspections and testing will follow. The railway is expected to improve connections for passengers and freight across Thailand’s north.
