The Central government is planning to construct underground rail tracks along a 40 km corridor to strengthen rail connectivity between NE and the rest of India, Railway Minister Ashwini Vaishnaw has said. The project is being presented as a strategic measure to overcome surface constraints and to provide a resilient link for passenger and freight movement. Planning is at an early stage and officials are conducting preliminary assessments of route alignment and technical feasibility. Detailed studies will determine the precise scope and engineering approach. The proposed underground alignment is intended to reduce land acquisition pressures and limit disruption in sensitive or congested areas while maintaining capacity for through services. Authorities expect tunnelling to mitigate environmental and social impacts compared with extensive surface works. Integration with existing networks will be a priority to ensure seamless connections within the NE rail grid and to long distance corridors serving other regions. Stakeholders are likely to focus on interoperability, signalling standards and freight handling facilities. Execution will require coordination across the Ministry of Railways and state administrations as well as clearances from environmental and urban planning bodies. Feasibility studies will address geology, groundwater considerations and the need for specialised construction techniques in varying terrain. Technical teams will assess options such as single bore tunnels, cut and cover sections and station designs tailored to local conditions. Procurement and financing strategies will be developed alongside risk assessments to guide implementation. The initiative is expected to be phased and subject to detailed budgeting and approvals before major construction commences. If realised, the corridor would enhance economic integration, shorten transit times and expand capacity for both passenger services and freight movements between NE and mainland markets. Officials say sustained planning and intergovernmental cooperation will be essential to translate the proposal into an operational link. The 40 km underground corridor is being framed as a long-term investment in national connectivity.