Sikkim currently lacks railway connectivity, which has raised concerns for residents and businesses. (Rangpo: Proposed station building)
What happened near Tunnel No. 7 in August 2025?
The risks became visible again in August 2025, when heavy rainfall triggered a landslide near Tunnel No. 7 at Rabijhora along the under-construction Sevoke–Rangpo railway route. Northeast Frontier Railway said the slope failure occurred about 30 metres from the tunnel and that the tunnel itself was not in danger. The Sevoke–Rangpo line was sanctioned in 2008-09. Environmental issues, land acquisition and forest clearances delayed progress, while construction began in earnest only in 2018. The Covid-19 pandemic affected work between 2020 and 2022, adding to the delays. As of September 2026, overall work is approximately 80% complete.
Because of the heavy rainfall, workers and equipment had been moved away from the area as a precaution. No casualties or injuries were reported, and officials said there was no loss of railway machinery or assets. The Teesta Bazar underground station was also reported to be nearing completion.
India’s railway network connects thousands of stations across the country, from busy metropolitan centres to remote towns and villages. The incident damaged a section of the protective structure at the tunnel approach. Debris removal and protective work were initiated after the incident. The incident highlighted the challenges of working on a railway project in landslide-prone Himalayan terrain. It also drew attention to concerns about slope stability along the route, although the incident alone does not establish that railway construction caused the landslide. Such conditions help explain why construction in the region requires careful planning, site-specific engineering and safety measures, and why progress can be affected by weather and ground conditions. The railway connection to Sikkim has been discussed for years, but the gap between sanctioning a project and beginning large-scale construction has been significant. The physical challenges of tunnelling and bridge construction in the hills have also made the project more demanding than a railway line across relatively level terrain.
Construction gathered pace later, with work beginning in earnest in 2018. The line stretches approximately 44.96 km, of which about 41.55 km lies in West Bengal and around 3.41 km in Sikkim. Approximately 38.6 km of the alignment — about 86% of the route — passes through tunnels. The project includes 14 tunnels, major and minor bridges, and five planned stations: Sevoke, Riyang, Teesta Bazar, Melli and Rangpo. The line stretches approximately 44.96 km, of which about 41.55 km lies in West Bengal and around 3.41 km in Sikkim The tunnels vary considerably in length, with the longest measuring around 5.3 km. As of September 2026, overall work is approximately 80% complete. The wider region has repeatedly experienced road blockages and landslides that affect movement along NH-10, a critical route connecting the Siliguri area with Sikkim. The latest completion target in December 2027.
Because of issues including land acquisition and forest clearances, the project was sanctioned in 2008-09, but work did not make substantial progress for several years. Environmental considerations have also affected the project. The proposed route passes through ecologically sensitive areas, including the Mahananda Wildlife Sanctuary region, and required clearances before construction could progress. The absence of a railway line has meant that Sikkim’s connectivity with the rest of India depends heavily on road links through neighbouring West Bengal, particularly the route from Siliguri towards Rangpo and Gangtok. The Sevoke–Rangpo railway line is a relatively short project by distance, but its engineering requirements make it particularly complex. Teesta Bazar is designed as an underground station, making it a notable feature of the project. The route also includes substantial bridge construction to negotiate the region’s valleys and uneven terrain. Engineers have adopted the New Austrian Tunnelling Method (NATM) for the tunnelling work. The method involves adapting support measures to the ground conditions encountered during excavation — an important consideration when working through variable and potentially unstable rock. A substantial portion of the railway line is underground partly to reduce surface disturbance across the mountainous landscape. However, tunnelling itself brings technical challenges, including difficult rock conditions and the need to maintain safety and stability during excavation. The route passes through the geologically and seismically challenging terrain of the young Himalayas. That makes the work more complicated than simply excavating a passage through solid rock: engineers must contend with the characteristics of the ground and the conditions surrounding each tunnel. The difficulty of building infrastructure in the Himalayas extends beyond railway tunnels. Steep slopes, heavy rainfall and landslides can disrupt construction and transport links, particularly during the monsoon. Traffic congestion and road closures can disrupt the movement of people and essential supplies. The railway project is intended to provide an additional transport link, reducing the state’s dependence on a road corridor that is vulnerable to monsoon disruptions. But building the line has also required construction teams to work carefully in the same challenging environment.
Earlier completion deadlines were revised as the project encountered these difficulties.
Will trains eventually reach Gangtok?
The 44.96-km Sevoke–Rangpo railway line, connecting Sevoke in West Bengal to Rangpo in Sikkim, is under construction and targeted for completion by December 2027. The project includes 14 tunnels, major and minor bridges, and five planned stations: Sevoke, Riyang, Teesta Bazar, Melli and Rangpo. When landslides, heavy rainfall or congestion disrupt NH-10, travel can become difficult and the movement of essential goods can be affected. A proposed railway line between Rangpo and Gangtok, approximately 34 km long, is being assessed as an extension of the Sevoke–Rangpo project. The 44.5-km Sivok-Rangpo railway line is being constructed at an estimated cost of Rs 17,124 crore. The proposed line, around 75 km long, could improve access to southern and western Sikkim. By road: NH-10 is a key route for reaching Sikkim from the Siliguri region. With the Sevoke–Rangpo line targeted for completion by December 2027, Sikkim is moving closer to its first railway connection.
Because of issues including land acquisition and forest clearances, the project was sanctioned in 2008-09, but work did not make substantial progress for several years. Because sikkim shares a border with China, the line also has strategic significance. The lack of railway connectivity therefore affects more than the availability of a train journey.
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