Known for its traffic snarls, the IT capital of India — Bengaluru — is all set to solve its traffic woes with the commencement of the 4.8 km underground corridor of Phase-I of its Namma Metro.
The latest addition to its existing Phase-I stretch, the 4.8-km underground journey from Cubbon Park to City Railway Station which was commissioned this April, takes merely 40 minutes as against almost two hours by road.
Phase-I consists of two corridors with a total length of 42.3 km. The East-West corridor is 18.1 km and the North-South corridor is 24.2 km, with 42 stations, of which seven are underground. The underground section on both corridors is 8.8 km in length.
With the opening of the East-West corridor, a total of 28 km of Phase-I has become operational. On the North-South line, the Metro is currently operational over a 10-km stretch in north Bengaluru from Peenya to Swastik Circle. Prior to opening the East-West line, 6.7 km in east Bengaluru had been operational on the East-West line.
And now, Bengaluru has its eyes set on the inauguration of the entire 24.2-km North-South corridor, scheduled for November; this will mark the completion of the entire 42.3-km Phase-I. Further, Phase-II will connect the outskirts; this is expected to be covered by 2020.
Several technologies were used in construction. There is a pile foundation (end-bearing piles and friction piles) and in viaducts, there is a precast supported single box girder with post-tensioning and pre-stressed girder with deck slab for stations, precast box girder with single cell for supporting two tracks with inclined webs, and rib finishes from ground level till the start of flare for pier cap provided.
A standard gauge of 1,435 mm has been adopted; further, the gradient of the superstructure is variable with a maximum up to 4 per cent. The horizontal alignment of the superstructure comprises straight, transition and curved stretches. The minimum design radius of the curvature is 120 m for the main line; the centre to centre of the track is 4.2 m in Phase-I and varies from 4 m and 4.2 m in Phase-II. The centre to centre track in scissors crossover is 4.5 m for 1:7 and 4.98 m for 1:9; loading corresponding to Modern Rolling Stock (MRS); ballastless track — a rebar provision for track concrete plinth integrated with deck slab. Also, regenerating Type-2 rolling stock is being used. The project proposes to use solar energy at depots and LED lights to save energy.
Further, high-quality materials for construction have been used as per the relevant IS code specifications. According to Siddanagouda Hegaraddi, Chief Engineer-Underground, Bangalore Metro Rail Corporation (BMRC), the rails used in turnouts are of 1,080-grade head hardened (imported) to resist wear and tear. The rolling stock was imported from South Korea and assembled at the BEML factory. The coaches are lightweight; made of stainless steel with automatic doors, they are aesthetically superior.
Equipment used during construction included tunnel boring machines (TBM); slurry and EPB shield; concrete pumps and boom placers; batching plants for concrete of capacity 100 cu m per hour; launching girders for erection of segments; hydraulic rigs; winches; concrete transit mixers; dumpers; trailer, trucks and tractors; vibro rollers; cranes; gantry cranes; front loaders; excavators; road rollers; asphalt mixing plant; and bitumen pavers.
Safety aspects include the continuous automatic train protection (ATP) and automatic train operation (ATO) system and fire-retardant materials with low fire load, low heat release rate, low smoke and toxicity inside. There are emergency doors at both ends and inter-car couplers to reduce injury in case of accidents. Further, lifts, ramps and tack tiles have been provided at all stations for senior citizens and the physically challenged.