IRCTC has a detailed procedure available for getting refund for regular Ticket( or i-Ticket) or E-Tickets in the following scenarios:
Train Cancelled By Railways.
Train running Late by More than Three hours.
Difference of Fare in case proper coach not attached.
Travelled without proper ID proof
Wrongly charged by TTE
Party partiallyÂ traveled
Passenger NotÂ traveled
The refund conditions and procedure to file TDR (Ticket DepositÂ Receipt) is given IRCTC TRD.