In Online Railway Reservation System,for booking the tickets online the intended user has to enter details like username and password.
Once the username and passwords are verified then he is allowed to enter the main system wherein he can select the destination, date and no of tickets.
For the purchase of the tickets he is asked for payment details (like credit card details etc).
The user is also provided with a provision of canceling the reservation where in the entire amount is credited back to his account.