You can reach Tirupati by air, rail or road.
There are trains that travel via Renigunta or Gudur, but do not touch Tirupati. In such cases, Renigunta (just 10 km from Tirupati) or Gudur (100 km from Tirupati), are convenient points to alight. From Renigunta/Gudur, you can reach Tirupati by train or bus.
Travelling by car is another good option. From Chennai, it takes nearly 4 hours to drive down to Tirupati. From Hyderabad it is nearly 11 hours drive to Tirupati which might be tiring but enjoying for the one passionate for driving.