Who says South India does not have Gatimaan. It is called Vaigai Express. - Thamizh Maran

Bangalore would disagree with your statement. Over the years, the city has developed in a very unplanned manner. Basically, the areas in the city which re currently the worst traffic hotspots, are practically impenetrable. Whitefield/KR Puram areas are one of the most nightmarish places you can go to. The purple line of the Metro that currently terminates at Baiyappanahalli is proposed to be extended to Whitefield, but the problem is that beyond the current terminus, the metro has to pass through very dense residential areas and Tech parks. Moreover, there are only 2 major roads that connect Whitefield to the rest of the city and both are always chock-block with traffic. They will have to be blocked for Metro construction and anyone living there will tell you that, such a move would spell utter disaster for traffic in these areas. The proposed metro link to the airport passes through some of...
more...

the oldest and densest residential and business areas in Shivaji Nagar etc, where it will be a herculean task to get the required land and construction clearance.
On the other hand, Bangalore has very good railway network coverage in the North, West and Eastern portions already in place. Even the upgrades these people speak of are only to provide a more comfortable service. With minimal upgrades ( nothing fancy here. No grand metro station complexes, or cosmetic constructions), they can be used for suburban service.
Metro might be more frequent, but in terms of efficiency, using the existing network is several orders of magnitude more efficient, especially in Bangalore.