The Delhi Metro has started work on finalizing stations on the alignment even as it awaits a nod from the group of ministers (GoM) for the third phase.
This phase will have a record number of 28 underground stations. The total number of underground stations in the network at present, including the two phases, is only 31. The reason, says the Delhi Metro, is an attempt to cause less traffic disruption. The new alignments in the third phase go through some of the most congested areas in the city.
According to officials of Delhi Metro Rail Corporation (DMRC), around 40% of phase III will be built underground and three different stretches will pass below the existing underground metro corridors in the city. These are the underground stretches from Sarojini Nagar to INA on the Mukundpur-Yamuna Vihar corridor, Indira Gandhi domestic airport to Kalkaji on the Janak Puri West to Kalindi Kunj corridor and Mandi House to ITO stretch. They will be passing over the Jehangirpuri-HUDA city centre line, the airport express link and the NOIDA-Dwarka line respectively.
Delhi Metro wants to use latest technology for the construction. Officials say that having a majority of the stations underground makes it a challenging task. “By constructing many underground stretches, DMRC will also be able to avoid causing damage to the existing infrastructure such as flyovers and roads,” a DMRC spokesperson said.
The total length of the underground corridor presently is 48.06km, while in phase III the underground stretch will be 41.044km. The first phase of Delhi Metro’s construction had 13.17km of underground metro lines while the second phase had 34.89km.
The longest underground section of phase III will be from IGI Airport (domestic) to Kalkaji on the Janakpuri West-Kalindi Kunj corridor, which will be 17.288km long. The Mukundpur-Yamuna Vihar corridor will have underground lines of 14.386km and the Central Secretariat-Kashmere Gate corridor will have a total of 9.370km underground lines.
“As per our plans, most of the underground work will be done through tunnel boring machines (TBMs) and new Austrian tunneling method (NATM). The stations will be constructed with the help of cut-and-cover technology,” the spokesperson added.
Initial tests such as geo-technical surveys, soil surveys, utility tests are being conducted by specialized agencies on all the new corridors. Tenders have been finalized for the construction of the Mandi House and Janpath stations on the Central Secretariat-Kashmere Gate corridor.