GoK is more intent on using the railway infrastructure for Cargo purposes for the proposed Devanahalli Business Park (DBP) and does not seem to be inclined to using it for commuters.
See the "sop" of railways mentioned in the EoI for the DBP :
"Existing railway line from Bangalore city and Yelahanka to Chikballapur passes through DBP, which would be available for cargo movement of DBP, if the Preferred Bidder of DBP project approaches South Western Railway as may be required, apart from connectivity through 6-lane National Highway-7 (NH-7) to various parts of India, including major ports of India."
Page #8, Point #5 of the EoI document: http://www.ksiidc.com/DBP...
IMHO, a "rejuvenated" line between Chandapura Railway Station (near Electronics City) via Whitefield and Marathahalli (ITPL area) and connecting via Byappanahalli thence to Yelahanka and finally to BIAL could be implemented.
This dedicated line can be made to operate during peak traffic periods, both air and road. For example, Friday evenings and Monday early mornings could be considered.
This is such a low hanging fruit that even according to experts such a Prof M N Sreehari, it would cost appx less than Rs. 4 - 10 crore per km for providing this vital link during peak hours to the IT sector towards BIAL.