Metro may cut tunnel section to 5-km in Gottigere-Nagawara line

The underground stretch that has become the Achilles' heel of Gottigere-Nagawara line is likely to be reduced to less than 5-km from the existing 13.7-km, a change that will help cut cost and save time for the BMRCL.

Sources in the Bangalore Metro Rail Corporation Limited (BMRCL) said except MG Road, Shivajinagar and Cantonment stations, the entire line will be elevated as per a proposal which is being considered seriously.

The corporation has been forced to think of restructuring the underground section after lowest bidding amount for the project - divided into four packages - overshot the BMRCL estimates by 69%. The 13.7-km section between Dairy Circle and Nagawara had 13 underground stations.

BMRCL Managing Director Mahendra Jain said they were considering all options, including negotiating with the companies to lower their bid prices.

"We have received bids with prices that go more than Rs 3,500 crore higher our estimates. We don't know whether negotiations will yield results considering that the rates quoted by them are so high. So, we are going back to the drawing board," he said.

Jain said restructuring the line was one of the several options that they were considering.

"We need four to six months for the retendering process. If we retender the project in the same format, the outcome is likely to be similar. Reducing the tunnel section will not only save us money but expedites the project and helps us save time," he said.

He said officials will now evaluate the technical factors and feasibility of such restructuring. BMRCL has said the construction of underground corridor costs Rs 500 crore per kilometre compared with the elevated section's cost of Rs 192 crore per km.

A senior official said their proposal for restructuring suggests that the underground section can start after Vellara Junction and a ramp connecting elevated line can be built after the Cantonment station.

"We are looking at a scenario where the tunnel section is not more than 4.5 km to 5 km. It will help reduce the cost by more than Rs 4,000 crore. Bannerghatta and Tannery roads are being widened, which gives space for a median that can support metro pillars," he said.