The Delhi Metro Rail Corporation has announced that the length of the tunnelled sections on its proposed Phase 3 will almost equal the total underground sections built so far on both Phase 1 and 2. The length of 5.7m-5.8m diameter tunnel on the city’s metro currently stands at 48km with 31 underground stations, whilst Phase 3 alone will involve the construction of some 41km of tunnel with 28 underground stations.
The first phase of Delhi Metro’s construction had 13.8km of underground Metro lines while the second phase had 34.9km.
The longest underground section on Phase 3 will run from IGI Airport (Domestic) to Kalkaji on the Janakpuri West – Kalindi Kunj corridor, which will be 17.3km long. The Mukundpur – Yamuna Vihar corridor will run underground for 14.4km, and the Central Secretariat – Kashmere Gate corridor will have a total of 9.4km of underground lines.
For the first time in the history of the Delhi Metro’s construction, three different tunnel sections on Phase 3 will pass below existing underground Metro lines in the city. These are:
1. The underground stretch from Sarojini Nagar to INA on the Mukundpur – Yamuna Vihar corridor which will pass below the underground section of the Jahangirpuri – HUDA City Centre line at INA.
2. The underground stretch from Indira Gandhi Domestic Airport (T2) to Kalkaji on the Janak Puri West – Botanical Garden corridor, which will pass below the underground section of the Airport Express Link near the Indira Gandhi Domestic Airport and Jahangirpuri – HUDA City Centre line near Hauz Khas.
3. The underground stretch from Mandi House to ITO on the Central Secretariat – Kashmere Gate Corridor, which will pass below the underground section of the NOIDA – Dwarka corridor at Mandi House.
Plans at present envisage most of the underground works excavated by TBMs and NATM, with stations constructed using cut and cover.
Presently, tests such as geotechnical surveys, soil surveys, utility tests are being conducted by specialized agencies on all of Phase 3’s corridors. Tenders have been finalized for the construction of the Mandi House and Janpath stations on the Central Secretariat – Kashmere Gate corridor. Tenders for the rest of the line will be let subsequently (see: http://www.delhimetrorail.com/tenders_civil.aspx)
Details of underground stretches:
| S. No | Phase 3 Corridors | Underground length (in kms.) | Underground stations | Names of underground stations |
| 1 | Mukundpur – Yamuna Vihar | 14.386 | 9 | Azadpur, Bhikaji Cama Place, Sarojini Nagar, INA, South Extn., Lajpat Nagar, Srinivaspuri, Ashram, Hazrat Nizamuddin. |
| 2 | Janakpuri West – Kalindi Kunj | 17.288 | 12 | Palam, IGD Airport, Vasant Vihar, Munirka, R.K Puram, IIT, Hauz Khas, Panchsheel Park, Chirag Delhi, GK Enclave, Nehru Place, Kalkaji. |
| 3 | Central Secretariat -Kashmere Gate | 9.370 | 7 | Central Secretariat, Janpath, Mandi House, ITO, Delhi Gate, Jama Masjid, Lal Quila, Kashmere Gate |
| S. No | Present Network | Underground length (in kms.) | Underground stations |
| 1 | Phase 1 | 13.17 | 13 |
| 2 | Phase 2 | 34.89 | 18 |
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