Milestone for Sevoke –Rangpo Railway Project

SUJAL PRADHAN, EOI, GANGTOK, JANUARY 23, 2023: With the formal breakthrough of tunnel no. T-11 of Sevoke – Rangpo Railway on Monday, January 23, the birthday of Netaji Subhas Chandra Bose, the ambitious and strategically important project is poised towards completion by 2024.

The tunnel, located in the Kalimpong district of West Bengal, was dedicated to the nation on the 126th birth anniversary of Netaji. This was the sixth tunnel on the project to have achieved breakthrough, but the first breakthrough in any tunnel more than three kms long.

Senior officials, including District Magistrate Kalimpong R.Vimala, Additional District Magistrate Tshering Y. Bhutia, Project Director Mohinder Singh from Ircon and Divisional Railway Manager Dilip Kumar Singh of Northeast Frontier Railway were present on the occasion.

The length of the main tunnel, located between Tarkhola and Tumlong khola in the Kalimpong district. is 3205 m and of the evacuation tunnel is 960 m. The evacuation tunnel connecting the NH10 and the main tunnel no. 11 was completed in December2022. 

The main tunnel traverses through vulnerable and challenging geological and seismic conditions of the lesser Himalayas, informed DRM Dilip Kumar Singh. Like all other tunnels on the Sevoke –Rangpo Railway project, to counter vulnerability of the groundmass, the latest and the most sophisticated tunneling technology, that is the. New Austrian Tunnelling Method or NATM was used for the tunnel. For the designing of the tunnel, Swiss consultancy team of Amberg Engineering had been engaged in this project. The execution team included top class and well experienced engineers from India, added the DRM.

The work was awarded to the private contractor firm concerned in September 2019. After the completion of approach roads and portal developmental work on both sides, the mining work was started in February 2020.Soon after that in March 2020, the Covid-19 pandemic broke out. The subsequent lockdowns hampered work for more than six months. When the work was gaining its pace again, in October 2020, “chimney formation and ‘open-to-sky’ situation” after a very low overburden zone was encountered. 

Finally, in January 2021,, after two and half months, the adversity was successfully tackled, and the tunneling team moved ahead with a new spirit. Since then, there was no looking back and the result was Monday’s smooth and timely breakthrough. More than 4 km of tunneling in T-11, including about 1 km of the evacuation tunnel, in only three years in spite of hurdles like Covid-19 and also poor geological conditions was described to be a “marvellous achievement."

The new rail link project connecting Sevoke in West Bengal and Rangpo in Sikkim is about 45 kms long and noted for14 tunnels, 22 bridges and five stations. About 38 kms of the entire project alignment is passing through tunnels. As much as 67 percent of tunneling work has already been completed. 

This is one of the prestigious ongoing national projects. On completion of this project, for the first time Sikkim will be connected via the railways. At present all the activities related to the construction of tunnels, bridges and station yards are going on war footing, with the target to complete the project by the end of 2024. In the second phase this line will be extend till Gangtok.