Hey Nivedita, Red bus is the best option for travelling from Chennai to Tirupati ..... You also get a little off if you have an app ... Go ahead with red bus ... Happy Travelling !!!
U can travel tirupati by train as well n it's very frequent... as u can go to tirupati or renigunta... n if u r going to temple then I suggest u to go by walk climbing d hills.. or if ur darshan tickets r booked than u can go by bus up the hill. don't get cheated by plps talk there...