L&T achieves major Tunnel Breakthrough on Delhi Metro Golden Line at IGNOU Station

New Delhi, India (Metro Rail Today): Larsen & Toubro Limited (L&T) has achieved another significant construction milestone on Delhi Metro’s Phase 4 network with the successful breakthrough of tunnel boring machine DZ1122 at IGNOU Metro Station. The breakthrough, completed towards the end of January, marks the third and final breakthrough for TBM-01 on the Golden Line, also known as Line-10, which will connect Aerocity to Tughlakabad across a 23.622 km corridor.

This achievement represents the ninth tunnel breakthrough for Package DC-09, a critical 6.51 km underground section between Kishangarh and Saket G Block. With this breakthrough, only one tunnel remains to be completed under the package, bringing the project close to a major construction milestone.

Complex Underground Works Through South Delhi

TBM DZ1122, a CRCHI Earth Pressure Balance machine, completed its final assignment by constructing an approximately 1.7 km long up-line tunnel from the City Forest Ramp at Hauz Rani to IGNOU Station. During this drive, the machine successfully executed a hidden breakthrough and safely navigated through the 130-metre-long Neb Sarai Station box, reflecting the high level of precision involved in the works.

The same TBM has earlier completed two other challenging tunnel drives on the corridor. In 2023, it bored a 1,267-metre tunnel between Chhattarpur Station and Kishangarh Station, followed by an 865-metre tunnel from the eastern end of Chhattarpur Station to Chhattarpur Mandir Station in 2024. Together, these drives underline the scale and continuity of underground construction on one of Delhi Metro’s most complex alignments.

Mrs. Mamta Shah, MD & CEO of Urban Infra Group, said the breakthrough highlights the maturity of India’s metro tunnelling capabilities. “Executing repeated TBM breakthroughs in dense urban areas like South Delhi requires not just advanced machines but also deep engineering expertise. The progress on the Golden Line demonstrates how Indian infrastructure projects are now matching global standards in underground construction,” she said.

Package DC-09 Nears Completion

Delhi Metro Rail Corporation had awarded L&T the ₹1,428 crore Package DC-09 contract in March 2022 with a completion timeline of 42 months. The package includes twin tunnels connecting Kishangarh Station with a cut-and-cover ramp near Saket G Block and four underground stations at Chhattarpur, Chhattarpur Mandir, IGNOU and Neb Sarai. Chhattarpur Station will also serve as an interchange with the Yellow Line, enhancing network integration.

L&T has deployed four TBMs on this package. While TBM-03 and TBM-04 have already completed their assignments, TBM-02 is currently boring the parallel down-line tunnel from City Forest Ramp to IGNOU Station. This final breakthrough for the package is expected within the next two weeks, after which all tunnelling works under DC-09 will be completed.

Dr. Vinod Shah, Director General of the Indian Chamber of Railway Industries, noted that such milestones are critical for keeping large metro projects on schedule. “Each TBM breakthrough reduces project risk and brings certainty to downstream works. The progress on the Golden Line reflects strong coordination between DMRC, contractors and equipment suppliers, which is essential for timely delivery of Phase 4,” he said.

Across the Golden Line, a total of 17 tunnel breakthroughs have been achieved so far, with works progressing simultaneously under multiple packages. As tunnelling advances towards completion, Delhi Metro’s Phase 4 Golden Line is steadily moving closer to becoming a new mobility backbone for South Delhi, offering faster, sustainable and congestion-free travel across the city.