My parents are aged and cannot climb up onto upper berth. I have booked first AC tickets for them. Though the tickets are confirmed, the coach/seat no. is not given. The rules on the Indian Railways site says that seat, coupe no. on first class AC are allotted at the time of chart preparation. However they cannot risk the journey if they are not sure that they would be allotted lower berths. How can I ensure that they get lower berths? will be much obliged for helpful inputs.