Mumbai Metro III may risk Rs 3,500 cr on ‘flawed design’
Jun 17 2014 , Mumbai
The apprehensions stated by various advisers consulting companies on the metro projects across India believe the alternative current traction model adopted by the Mumbai Metropolitan Region Development Authority (MMRDA) for the third phase and the lack of second depot or yard to meet any eventuality apart from issues of environment and security clearances while building the tunnel under the Mithi river and airport could mean an additional burden of Rs 3,500 crore on the exchequer..
As against the global norm of direct current model used in 99 per cent of the 185-odd metros across the world, Mumbai and India would be exceptions. Under the AC model the rake has to carry the substation in the train that increases the dead weight and reduces efficiency or speed by 10 to 15 per cent, compared with the DC model where the substations are offsite and the trains don’t have to carry them on the coach. It also increases the height and width of the train leading to increased size of the tunnels.
Anil Jangid, founder director of Leap Infrastructure, that prepared the detailed designing of the Bangalore, Ahmedabad and the Kochi Metro, believes, “In Bangalore Metro, which runs on DC model, the weight of six coach train is 225 tonne, while in Chennai running on AC model the same train weighs around 250 tonne.”
“The tunnel size hence goes up by 5-10 per cent in the AC model due to size of the coaches, resulting in an increase of Rs 7 crore per route km under the AC model, where the cost of tunnel is Rs 150 crore per route km,” Jangid adds.
Also, in the DC model, the trains are cheaper by 5-10 per cent, depending on the certification. For the 33 km stretch of the project, about 12 cars or coaches would be required per route km, which equals to a total of around 400 coaches. If the DC trains are cheaper by 5-10 per cent, the cost savings per route km would be around Rs 6-10 crore, said the official quoted above.
Although the direct cost of AC train is lower compared with DC, the overhead cost in terms of tunnel cost, per route km cost and the cost of the trains make it far more economical to go for the DC model believe experts.
Larsen & Toubro, which pre qualified for the project and is awaiting the final bid opening says it will wait for the finer imprint after the bid opens and they will sort out all issues related to design, structure and method of constructions. “Even in the Hyderabad Metro we waited for the final right of way clearances before we started the construction work in 2012, despite winning the project in 2010. We will do the same if we are awarded the project in Mumbai as well. However, the difference in Mumbai is that we would just be contractors while the project concession would be with the MMRDA. Hence, it would be the sole responsibility of the MMRDA to choose the model they prefer, but it should be viable and worthy of implementation,” a spokesperson for L&T said.
Sudesh Kumar, a former railway board member, believes India has been replicating the old AC model out of its experience across India in the railway networks without looking at the positive side of the DC model, which helps in saving costs and reducing the chances of reduced disposal of dug outs, which is a major concern. Around 11 bidders have pre-qualified for phase III, including L&T, Gammon Infrastructure and Essel Infrastructure
The 32 km Mumbai Metro Phase II is in process of being scrapped, as R-Infra-promoted Mumbai Metro Transport Private Ltd that signed the concession agreement for Metro II in 2010 failed to receive the right of way and environmental clearances for a car depot on mangrove land in Mankhurd.