The tunnel's construction was significantly delayed by World War I, which resulted in the internment of the German lead engineer, Emil Eisenhofer, by the Thai government.
During the tunnel's construction, many laborers suffered from malaria outbreaks, leading to the establishment of the nearby shrine dedicated to Chao Pho Khun Tan.
It is the only railway tunnel that connects the northern region to the rest of the country's rail network.
The interior is reinforced with high-quality bricks sourced from local production kilns active during the early 20th century.
The tunnel represents the final engineering challenge that allowed the Northern Line to reach Chiang Mai in 1921.
Khun Tan Tunnel is the longest railway tunnel in Thailand, measuring 1,362 meters in length. It serves as the primary gateway connecting the Central Plains of Thailand to the northern province of Chiang Mai. Constructed between 1907 and 1918, the tunnel was engineered by German civil engineer Emil Eisenhofer. It is situated within the Khun Tan Mountain Range at an elevation of 578 meters above sea level. The tunnel pierces through the border between Lamphun and Lampang provinces. It remains an active component of the State Railway of Thailand's Northern Line. The structure is characterized by its signature brick-lined interior and historical engineering design. It is located directly adjacent to Khun Tan Railway Station, which is the highest station in Thailand.
The north entrance of the tunnel, which allows for a symmetrical shot of the brick portal against the lush mountain backdrop.
Visit the small memorial shrine near the tunnel entrance to pay respects, as it is culturally significant to railway workers and locals.
Walk the short trail leading to the tunnel entrance for a clear view of the portal architecture.
Combine your visit with a hike in the surrounding Doi Khun Tan National Park for better vantage points of the railway tracks.
Attempting to walk through the tunnel interior, as it is active, narrow, and extremely dangerous due to limited clearance.
Maintain a respectful distance from the active train tracks and do not block the path of railway workers.
