The system is still there but not on all trains I suppose.
you have number of buses almost round the clock from just outside the station to tirumala. the buses dont ply when the ghat road is closed between 12 midnight to 3 in the morning. You cand buy single and or return ticket which cost Rs.24 and Rs.44 respectively. You can buy ticket from traffic control post opposite railways station or at alipiri counter as these buses dont have conductors and have only drivers. the driver will take you to the ticket counter do not worry about it.