DMRC achieves tunnelling breakthrough on Phase 4's Golden Line at Tughlakabad

New Delhi: The Delhi Metro Rail Corporation (DMRC) has marked another significant milestone in the execution of its Phase 4 project with the successful completion of an underground tunnel between Tughlakabad and Tughlakabad Railway Colony on the upcoming Aerocity–Tughlakabad corridor, also known as the Golden Line.

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The breakthrough of the Tunnel Boring Machine (TBM) was achieved today at the Tughlakabad Railway Colony site in the presence of Shri Naveen Gulati, Member (Infrastructure), Railway Board, and senior DMRC officials.

A massive 91-metre-long TBM was deployed to construct the 0.792-kilometre-long tunnel, which forms part of the twin parallel tunnels being built for up and down movement on this stretch. The construction was carried out by civil contractor M/s Afcons Infrastructure Ltd.

The newly completed tunnel lies at an average depth of 18 metres below ground and comprises 559 concrete rings, each with an inner diameter of 5.8 metres. Built using the Earth Pressure Balancing Method (EPBM), the tunnel is lined with precast concrete segments that were manufactured at a fully mechanized casting yard in Mundka. These segments were treated using a steam curing system to ensure early strength.

Strict safety measures were followed throughout the tunnelling process. Highly sensitive instruments were installed on nearby structures to monitor ground movements and ensure zero settlement, especially under existing built-up areas.

The Aerocity–Tughlakabad corridor includes approximately 19.343 kilometres of underground sections and is a major component of the total 40.109 kilometres of underground tunnelling approved under DMRC’s Phase 4 expansion plan.

TBMs, widely used by DMRC since Phase 1, have become indispensable for tunnelling operations in densely populated urban environments. During Phase 3, which included nearly 50 kilometres of underground metro lines, around 30 TBMs were deployed in the National Capital Region, significantly enhancing construction efficiency while minimizing disruption to surface infrastructure.

The successful breakthrough at Tughlakabad marks continued progress toward expanding Delhi’s metro network and improving connectivity in the southern and central parts of the city.

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