You have forgotten to ask why Congress-Branch:Karnataka opposes Cauvery water to TN? Remember SM Krishna's padayatra?
Railway development is taking place because of TN's representation in Rly minstry and it is not correct to link everything to everything else. If that be the case, you can also ask as to why nothing was done all these years, even though the aethists were ruling TN for a long time?
As a Tamil, I am happy about the development in TN, whoever is the reason for it. After all, that is why votes are cast for aethists not because of aethist propoganda.