The Delhi Metro Rail Corporation (DMRC) on Saturday achieved a significant construction milestone with the completion of the underground tunnel between Maa Anandmayee Marg and Tughlakabad Railway Colony Station on the Tughlakabad-Aerocity corridor of Delhi Metro’s Phase-IV which is also known as Golden Line.

The breakthrough of the Tunnel Boring Machine (TBM) at the Tughlakabad Railway Colony Station site of the Delhi Metro took place in the presence of Dr. Pankaj Kumar Singh, Minister for Health and Family Welfare, Transport, Information Technology, Government of NCT of Delhi, Dr. Vikas Kumar, Managing Director/DMRC and other senior officials.

Advertisement

During his address, Dr. Pankaj Kumar Singh lauded the engineering precision and tireless dedication of the DMRC engineers, construction teams and on-ground workers. He emphasised that such breakthroughs reaffirm the Central Government’s commitment to modern, sustainable urban infrastructure that enhances ease of living, reduces road congestion, and contributes to environmental sustainability.

“Ever since our government came to power in Delhi, we have worked to restore the public’s trust—and this is now clearly visible in the progress of long-delayed metro phases. What was once stalled is now moving at full speed. Today’s breakthrough is not just a technical achievement, but a symbol of renewed momentum. In many ways, this event serves both as an inspection and a celebration. Going forward, we will further accelerate metro expansion and ensure that Delhi’s citizens receive the quality infrastructure and services they truly deserve,” he said.

A TBM broke through this morning at Tughlakabad Railway Colony Station after boring a 0.792-kilometre-long tunnel. This tunnel breakthrough was achieved using a mammoth 96-metre-long TBM. Two parallel circular tunnels for up and down movement are being constructed on this stretch. The breakthrough on the other parallel tunnel is expected to be achieved in July 2025.

This new tunnel has been constructed at an average depth of approximately 18 meters. About 566 rings have been installed in the tunnel, with an inner diameter of 5.8 meters. The tunnel has been built using the proven technology of EPBM (Earth Pressure Balancing Method) with a concrete lining made of precast tunnel rings. These tunnel rings were cast at a fully mechanized casting yard set up at Mundka. The concrete segments were cured with a steam curing system to achieve early strength.

All necessary safety precautions were taken during the construction of the tunnel below the existing built-up structures. Ground movements were monitored with highly sensitive instruments fixed on nearby structures, ensuring that there was no settlement anywhere.

As part of the Phase 4 work approved so far, 40.109 kilometres of underground lines are being constructed. The Aerocity-Tughlakabad corridor has underground sections totaling 19.343 kilometres.

A TBM is a machine used to excavate tunnels with a circular cross-section through various soil and rock strata. They can be designed to bore through anything from hard rock to sand. TBMs have revolutionized tunneling work worldwide, enabling tunnels to be bored without disturbing buildings and other surface structures.

TBMs are particularly useful for underground tunneling work in congested urban areas. DMRC has been using TBMs for its tunneling work since Phase 1. In Phase 3, when approximately 50 kilometres of underground sections were built, about 30 TBMs were deployed in the national capital.