25.6.12

MEGA to employ third rail system

Ugly overhead electrical cables are an eyesore in most global metro rail projects, but the Ahmedabad-Gandhinagar metro rail will employ the third-rail system (TRS). This technology provides electric power to a train through an inverted U-shaped insulated conductor rail placed alongside the track on the ground itself. A connector from the metro rail will slide on the TRS to draw power. This technology is being used in the Bangalore Namma Metro rail but is absent in the Delhi metro. 
Gujarat’s MEGA metro rail has decided to float fresh bids to invite expression of interest (EOI) for supply, installation, testing and commissioning of tracks for the metro rail — including the TRS. 
As far as costs are concerned, the TRS is cheaper to install, when compared to overhead wire contact systems. This is because no structures are required for carrying the overhead contact wires. Besides, there is no need to reconstruct overbridges or tunnels to provide clearances. There is also much less visual intrusion on the environment. Bangalore metro rail uses 750 volt TRS systems and is considered to be among the safest and best in the world.
The first phase of the project will include 44 kilometres of elevated tracks and multiple stations on the route. 
There is a special mention of the fact that along the first phase, MEGA could also undertake underground corridors in certain stretches. These underground stretches are possible in the walled city area, where Archaeological Survey of India (ASI) regulations and the problem of weak structures are encountered. 

Sources in the Gujarat Industrial Development Board (GIDB) say that the metro can tap 15 to 18 percent of freight movement within Ahmedabad, which happens on weekdays. 
Senior officers at MEGA also pointed out that the height of the metro rail elevated corridor would not be as high as it is in Delhi. This has been decided keeping in mind the future need of building multi-level flyovers. In addition, MEGA, which is the special purpose vehicle for the metro project, is planning a broad gauge network.

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