Delhi Metro: Tunnel Boring Machines Get Down To Work On 23.62 Km Aerocity-Tughlakabad Corridor


The Delhi Metro Rail Corporation (DMRC) last week achieved a major milestone towards construction of Silver line by starting the tunnelling work.

The 23.62 km Silver Line is a part of Phase-4 project and will connect Delhi Aerocity and Tughlakabad in South Delhi via 15 stations.

The first Tunnel Boring Machine (TBM) on the Aerocity-Tughlakabad Corridor started its drive on 3 March to bore a 1.27 km long tunnel between Chhatarpur and Krishnagar stations.

A TBM is a machine used to excavate tunnels with a circular cross-section through a variety of soil and rock strata.

They can be designed to bore through anything from hard rock to sand. TBMs are especially useful for underground tunneling work in congested urban areas.

TBMs have revolutionized the way tunneling work is done worldwide as tunnels can now be bored without disturbing the buildings and other structures on the surface.

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

Earlier last week, the Delhi Metro Rail had awarded the signalling contract for the Silver Line to Alstom Transport India at a value of Rs 219.59 crore.


As part of the Phase 4 expansion of the Delhi Metro, DMRC is constructing 65.20 km of new lines across three different corridors in the national capital with 45 metro stations.

The three new lines are:

  • Magenta Line Extension: Janakpuri West-RK Ashram Marg (28.92 km).
  • Pink Line Extension: Majlis Park-Maujpur (12.55 km).
  • Silver Line: Tughalakabad to Aerocity (23.62 km) — the line will connect the operational Violet and Airport Lines from the respective ends.

As part of the Phase 4 work approved so far, about 27 km of underground lines will be constructed.

The development work on Phase 4 had begun in December 2019 with a ground-breaking ceremony, however, it was hit after the outbreak of the Covid pandemic in March 2020 in the national capital.

All the corridors under this phase of metro expansion will be completed by September, 2025.

312 Coaches

The Delhi Metro Rail in October last year signed a contract with Alstom Transport India for procuring 312 metro coaches (52 trains) for Phase 4’s corridors.

While the Janakpuri West-RK Ashram Marg extension of the Magenta Line will get 144 new coaches (24 trains), the Majlis Park-Maujpur extension of the Pink Line will get 90 new coaches (15 trains).

In addition, 78 standard gauge coaches will be procured for the Tughlakabad to Delhi Aerocity corridor.

All these trains will be compatible for driverless operations and will be manufactured in Alstom India’s facility at SriCity near Chennai.

The Delhi Metro currently operates on a network of 391 km with 286 metro stations (including the Noida-Greater Noida corridor and the Rapid Metro, Gurugram).