L&T Completes Tunnelling for Delhi Metro Phase IV Golden Line Aerocity–Tughlakabad Corridor

Larsen & Toubro (L&T) has completed the entire tunnelling scope for the Phase IV Golden Line (Aerocity–Tughlakabad Corridor) of Delhi Metro Rail Corporation (DMRC). The milestone was marked by the seventh and eighth tunnel boring machine (TBM) breakthroughs at the retrieval shaft near IGNOU Station.

A key highlight of the project was the execution of stacked tunnelling, a first for both L&T and DMRC. Due to limited surface space near Neb Sarai, the station required a two-level platform configuration, leading to vertically aligned twin tunnels instead of the conventional parallel arrangement. This required stacking two large TBMs vertically within the tunnel stretch and during the station drive-through with a precision tolerance of just 100 mm.

The project team also navigated complex urban challenges, including tunnelling beneath more than 650 multi-storey buildings and managing construction logistics during restrictions imposed under the Graded Response Action Plan (GRAP).

In total, L&T completed eight tunnel drives covering approximately 10,650 metres while maintaining strict safety and quality standards, marking a significant milestone in the development of the Delhi Metro Phase IV network.