Suraj wrote: They could only do this effectively once the trackage and signalling could support such throughput without slow trains holding up fast ones.
Then we should really see what the Chinese have done. No harm in copying a good working system. Because this issue of too many trains on too less a track is the problem which IR is also facing. In many areas the trunk routes are saturated. With the existing signalling systems, new trains cannot be introduced. Slow moving passenger/commuters share the same track (and the time slots with minor differences) with Express and Superfast trains. The divisional controllers sitting at the Div H.Q have to do the jugglery and instruct Station Masters en-route to pull over some trains, and allow some others to proceed etc. These are all done using telephones.
Even without planning for Shinkansen type bullet trains, IR can make a lot of improvement (which also has a psychological impact) if the speed levels are increased marginally - but all across the board. So DEMUs,MEMUs for local commuter/passenger trains, and more "train sets" based trains for a few special trains (Intercity Express, Shatabdi etc.) for a start. This itself may improve IRs image.