In a key advancement under Delhi Metro’s Phase 4 expansion, the city recorded a significant breakthrough as Tunnel Boring Machine (TBM) “Shalini” completed a 1.55 km underground tunnel to Vasant Kunj station on the Golden Line, reinforcing progress in India’s sustainable urban transit agenda.
On 25 June 2025, TBM S64B—named Shalini—successfully emerged at Vasant Kunj, completing the eastbound tunnel between Kishangarh and Vasant Kunj. This feat comes after a similar breakthrough was achieved in March for the westbound tunnel, reflecting the Delhi Metro Rail Corporation’s (DMRC) continued engineering momentum in constructing the 23.6 km Aerocity–Tughlakabad corridor, one of the most ambitious arms of the Phase 4 development. The TBM, stretching 91 metres with a cutter head diameter of 6.61 metres, carved its path at depths varying from 15 to 30 metres underground. The tunnel consists of over 1,100 precast concrete rings, each with an internal diameter of 5.8 metres, offering structural stability through Earth Pressure Balance Method (EPBM) technology—designed to prevent soil collapse and mitigate risks to surface structures.
Awarded at a contract value of ₹1,611.74 crore, this segment—referred to as Package DC-08—covers 6.1 kilometres and includes the construction of four key underground stations: Aerocity, Mahipalpur, Vasant Kunj, and Kishangarh. The corridor is part of the broader Phase 4 blueprint which will add 112.3 km to Delhi Metro’s network, with 40.1 km laid underground. This ensures a significantly lower surface disruption footprint while enhancing carbon-neutral mobility solutions. What sets this achievement apart is not just the scale, but the environmentally conscious engineering that underpins it. Both TBMs deployed—Shalini and her counterpart—are refurbished, an initiative that underscores the Metro’s commitment to circular infrastructure practices. Additionally, all tunnel rings are produced on-site using steam curing, a method that not only accelerates production but also slashes carbon emissions compared to conventional approaches.
The Vasant Kunj breakthrough adds a crucial link to the Golden Line, a route poised to decongest major city arteries and provide sustainable alternatives to fossil-fuel-dependent transport. More importantly, the line promises enhanced accessibility for women, the elderly, and persons with reduced mobility—pushing the envelope for equitable urban transit. Delhi Metro’s approach balances cutting-edge construction with social and environmental stewardship. Underground tunnelling supports long-term ecological goals by preserving heritage zones, reducing vehicular dependency, and limiting air and noise pollution in densely populated neighbourhoods.
With Shalini now set to continue tunnelling westward, this success highlights Delhi Metro’s operational excellence, timely delivery, and strategic focus on eco-sensitive expansion. Each tunnel segment marks progress not just in physical infrastructure, but in reimagining how India builds cities—prioritising inclusivity, sustainability, and resilience in the face of urban sprawl. As India aims to become a global model for green mobility, Delhi Metro’s steady march underground demonstrates the potential of public infrastructure projects to accelerate net-zero targets while improving urban quality of life.
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