Maligaon: In another milestone achievement, the Sivok-Rangpo Rail Project achieved a breakthrough in Tunnel No. 12 on December 24. This is the fifth main tunnel breakthrough in this project which was done in presence of officers of North-east Frontier Railway, IRCON international limited and construction agency CS-Dhorajia along with local administration of West Bengal. The length of Tunnel No. 12 is 1,406 metre located between Tarkhola and Shukia Khola in Kalimpong district of West Bengal. The tunnel traverses through challenging geological conditions of the lesser Himalayan range.