Underground Railway Tunnel Through Siliguri Corridor: Securing India's Lifeline to the Northeast

INTRODUCTION

The Siliguri Corridor, a narrow strip of territory, connects mainland India to the entire northeastern region. Situated in northern West Bengal, infamously known as the ‘Chicken’s Neck’, it is India's most vital and vulnerable strategic location. The connectivity of Assam, Arunachal Pradesh, Meghalaya, Manipur, Nagaland, Mizoram, Tripura, and Sikkim with the rest of the country through road, railway, oil pipelines, power lines, as well as troop movement, depends on this corridor. The strip is locked between Nepal, Bangladesh, with Bhutan and China just a few kilometres away from the border. 

Illustration by The Geostrata

In February 2026, the Government of India, to connect as well as safeguard the region, announced the establishment of a 40-kilometre underground railway tunnel connecting Dumdangi to Bagdogra via Tinmile Hat and Rangapani. Union Railway Minister Ashwini Vaishnaw described the project as a foundation of not only the growth and development in the region, but also a major plus point from a security and strategic point of view. Furthermore, Chetan Kumar Srivastava, General Manager of Northeast Frontier Railway and Chief Construction Officer, Hitendra Goyal (NFR), the Chief Construction Officer, confirmed the laying of underground railway tracks and conversion of two-line tracks to four-line ones.

The tunnel falls under the Katihar Division of the Northeast Frontier Railway and passes through Darjeeling, Uttar Dinajpur, and Kishanganj districts. It will be constructed using tunnel boring machine technology, electrified on a 2×25 kV AC system, and designed for 25-ton axle loads, capable of moving heavy military equipment as efficiently as civilian freight. Its proximity to the Bagdogra Air Force Station and Bengdubi Army Cantonment makes it a critical enabler of air-rail logistics integration for defence operations.

THE STRATEGIC THREAT

Looking North and East can help you understand the need for an underground mobility network. The ‘Chumbi Valley’, which is in very close proximity to the corridor, lies in Chinese-occupied Tibetan land that stretches south between Sikkim and Bhutan. The construction of air bases, road networks, and the deployment of air defence systems and missile systems on Tibetan soil have significantly helped China’s Western Command mobilise its troops in India’s Near East. The Chinese are 130 kilometres in distance via the Chumbi valley, which will in longer terms bring instability in the North-East state of India. 

Map by The Geostrata

The 73-day military standoff between India and China resulted in the withdrawal of the Chinese soldiers. The standoff was triggered when the Chinese started construction of a road, just 50 km from the northern edge of the corridor. The standoff became a flashpoint in relations between New Delhi and Beijing irking India to recalibrate its border security policy, drawing valuable lessons, one being that border negotiations do not guarantee peace over the frontlines. Given the significance and delicate nature of the region, the Indian government recognizes the urgent necessity to prioritize area security. The Chinese have already assessed their strengths and vulnerabilities in the region and have considerable coercive leverage over Indian strategic planning, according to analysis.

Since the recent dispute over the border, the Chinese have been keen on cornering India not just with their military or economic influence but also by building better bilateral relationships with countries that are in proximity to India. One of the prime examples of this has been with Nepal. China plans to build up a significant industrial zone at Damak in the Jhapa district, which is approximately 55 kilometres from the western frontier of the corridor along the India-Nepal border.

These projects can also be considered as part of their monitoring activities, especially on troop movement. Another dimension that has come to light is the report of the Chinese interest in reviving the  World War 2-era Lalmonirhat airbase. The Lalmonirhat airbase is located in northern Bangladesh near the Indian Border, just over 130 km from the Siliguri Corridor, which means any hostile military presence there could directly threaten India's only land link to its entire Northeast.

The China-Bangladesh relationship has taken a dramatic turn after the fall of Sheikh Hasina back in August of 2024. Furthermore, the 2026 election in Bangladesh is not a political event in the neighbourhood but a strategic variable that shapes the security architecture surrounding one of India’s most critical geopolitical chokepoints.

The Bangladesh Nationalist Party comes back to power, and Jamaat-e-Islami’s electoral victories in constituencies close to the border vindicate a current empirical catalyst to investigate whether changes in Dhaka’s political ethos create strategic discomfort in New Delhi. The goal is not to panic but to assess the vulnerabilities, such as how diplomatic alignment, insurgent sanctuary denial, migration control and intelligence cooperation can change under a changing political regime. 

INDIA'S UNDERGROUND ANSWER

A surface railway, no matter how well maintained, is always visible to satellite surveillance, vulnerable to strikes and prone to natural disasters. All these disadvantages are eliminated by a subterranean railway. It continues to function flawlessly in the face of severe weather, and as the project progresses, more security features, such as surveillance, physical protection, and strategic redundancy, will be gradually found and incorporated into its larger defence architecture.

“For decades, the 'Chicken's Neck' has been used as an intimidation tactic by anti-national forces. The proposed underground rail link marks a major strategic breakthrough", wrote Assam Chief Minister Himanta Biswa Sarma. This statement doesn’t just reflect the security and geopolitical primacy of the region but also carries a huge economic implication for the locals, as it will bring in investments, generating employment. A secure, high-capacity rail route will lower freight costs, support India's Act East policy, and position the region as a genuine gateway to Southeast Asia through BIMSTEC, Kaladan Multimodal Corridor and the India-Myanmar-Thailand Trilateral Highway. 

The subterranean tube is a component of a broader consolidation project. The Trishakti Corps has carried out extensive mobility drills throughout the area, three new military garrisons have been built closer to the corridor and operation through intelligence has been strengthened. India is now not only protecting but also bolstering the region. At one point, Sadhguru, a renowned yogi, mystic and author, suggested the transformation of “Chicken Neck into an Elephant Trunk”, meaning that India should transform its fragility into strength. 

In addition to the infrastructure development, it is a case of defensive recalibration, an understanding that safeguarding the North East now requires tough, redundancy-based logistics, including through accelerated infrastructure projects like trans-Arunachal highway networks, expanding airbase capability across the Northeast, in anticipation of both conventional and hybrid threats.

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BY ABHIGYA LANGEH

COVERING PEOPLE'S REPUBLIC OF CHINA

TEAM GEOSTRATA

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