Khun Tan Station, at the northern end of the tunnel, is the highest railway station in Thailand at an elevation of 578 m.[2]
History
Historically the Khun Tan Range was a formidable natural barrier between the Kingdom of Chiang Mai and the Central Plain of Siam. The Khun Tan Tunnel was built in 1907 under the southern part of the range. It reduced the difficulties of travel between the cities of Bangkok and Chiang Mai. The tunnel took eleven years to complete. Construction was disrupted owing to the arrest of its German engineers in World War I. Emil Eisenhofer, the German engineer who directed the Khun Tan Tunnel project.[3]
Originally the tunnel had been intended for standard gauge, therefore there is extra space inside the tunnel after its having been regauged to meter gauge.[4]
References
^From a list of tunnel data provided by the Information Bureau of the State Railway of Thailand