Tunnelling work on Phase-III of Metro completed

With the construction of a 1.25 km long tunnel between Vasant Vihar and Munirka on the Janakpuri West- Botanical Garden Magenta Line the Delhi Metro has completed the tunnelling work of Phase- III of the network.

The construction of the tunnel, which started in October last year, consists of 904 rings and has been made 20 metres below the surface. With this tunnel breakthrough, the Delhi Metro Rail Corporation (DMRC) claims to have completed one of the largest ever tunnelling projects taken up in any urban area in the world, in which a record 30 Tunnel Boring Machines (TBMs) were used to bore close to 80 kilometres of underground tunnels (combining the length of both tunnels for to and fro movement of trains).

The total underground corridor length in Phase 3 including the stations is about 54 kilometres. On the 38 kilometre long Janakpuri West – Botanical Garden corridor where the tunnel breakthrough took place on Monday in presence of Metro officials, about
23 kilometres are underground.

The new tunnels passes below already operational elevated viaducts of Delhi Metro at three locations namely at Janakpuri West below Blue Line, near IGI Airport below Airport Line and near Kalkaji Mandir below Violet Line. At Hauz Khas, the new tunnel also passes below the already operational tunnel of Delhi Metro’s Yellow Line.

A 1.4 kilometre long tunnel between Shankar Vihar and Vasant Vihar on this section was also fraught with challenges as it passed below the rocky Aravali ranges and special Rock TBMs had to be pressed into service for the drive. On the 59 kilometre long Majlis Park – Shiv Vihar Pink corridor, about 19 kilometres are underground.

This is the longest ever Metro corridor of the DMRC network. On this section, the new tunnels have passed below already operational viaducts at three locations (at Azadpur below the Yellow Line, Netaji Subhash Place below the Red Line and at Lajpat Nagar below the Violet Line).

 The new tunnel also passed below the operational Metro tunnel of Yellow Line at INA.
Delhi Metro’s longest tunnelling drive of 1.6 kilometres from Ashram to Nizamuddin also falls on this section.

At some locations, the TBMs are now being retrieved following the completion of work.
The tunnelling work on both the Magenta and Pink lines faced hindrance since these corridors mostly pass below the arterial Outer Ring Road and Ring Road of the city, which have heavy traffic round the clock.

The 9.37 kilometre long Central Secretariat – Kashmere Gate corridor is also entirely underground. While the section up to ITO has already been opened, trial runs are in progress on the remaining stretch up to Kashmere Gate.