there are no such rules on IR. if you miss a train due to delayed arrival of previous train in case of two separate reservations, you are not entitled to any refund or compensation.
In case of a telescopic ticket with two reservations (also known as Blank Paper ticket even though its not on a blank paper!) on the same ticket, you have paid the fare for the second leg and can board another train on the same route but cant automatically board a reserved coach. You can check with the TTE of the other train and if he allows, you can take an available berth.