I agree and bangalore should look at introducing local trains using the existing track. I dont know why they are not trying for this. Metro will take atleast another 5-7 years and meanwhile city will be in choas with all roads becoming into big pits regularly. Presently we have the track
Doddaballapur(Nr new Intn aport) to City, Whitefield, Hosur (Covering Marathahalli, HAL).
They can also run from Kengeri, RPC layout, to city and other places.
Even HAL can be extended to train facility by avoiding lots of buses and other trafic.
Many areas can be covered by the existing track itself, but yes it requires some kind of maintainance..