I happen to travel through this chain frequently
/chain/6438 and the thing is there is never time to get down at Vridhachalam Junction and get tickets for the unreserved train , so i and a lot off people simply switch trains and start our journey while the railway officials even watch without any intention to stop us. I dont bother since this is a common practice on this route . But is there a legal way to do this. The ticket is merely 10 rupees which i am willing to buy if it is available at the platform itself.