When you get a confirmed ticket for Indian Railways, then it may not be a good choice to cancel your ticket or miss the train as you are confirmed a full berth and seat. It is important that you reach the boarding station on time so, that you may not miss your train.
However, if for someone emergency you are not able to reach the station and miss the train then it is important to find out what are your chances for a refund and how can you reach the destination.
If you somehow miss your train with a confirmed ticket then you will have to buy another reserved from the station (if available) to travel in the reserved coaches.
As far as the refund goes, then you may or may not get a refund from Indian Railways by filing a TDR or Ticket Deposit Receipt. In the TDR per the extant rules, you will have to cite the exact reasons as to why you were not able to reach the station and board the train.
Depending on your application and your reasons as of why you were not able to travel, you may or may not get the refund.
TDRs can be filed within one hour after the departure of the train from the charting station. After that, TDRs can’t be filed and you will lose the opportunity to get a refund.
Since the chart has been prepared for the train, you can not cancel the ticket after the preparation of the chart as per the rules.