The Delhi Metro Rail Corporation (DMRC) on 7th May 2025 achieved a significant construction milestone, with the TBM breakthrough at  Tughlakabad Railway colony station. The 96-m-long TBM EPB completed the 0.792-km tunnel between Maa Anandmayee Marg and Tughlakabad Railway colony station on the Tughlakabad-Aerocity corridor of Phase-IV which is also known as Golden Line. 

Two parallel tunnels for up and down movement are being constructed on this stretch as part of the Aerocity–Tughlakabad corridor. 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 m. About 566 rings have been installed in the tunnel, with an inner diameter of 5.8 m. 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 IV work approved so far, 40.109 km of underground lines are being constructed. The Aerocity-Tughlakabad corridor has underground sections totalling 19.343 km. 

DMRC has been using TBMs for its tunnelling work since Phase 1. In Phase 3, when approximately 50 km of underground sections were built, about 30 TBMs were deployed in the national capital. 

Click here and in/11 for tunnelbuilder archive and also visit https://delhimetrorail.com/. 23/25.