As of now you can claim half refund of your ticket if you cancel the ticket within two hours of departure. But yes, you can claim refund only if the train is cancelled, air conditioner is not working in an AC coach or if the passenger has to travel in a sleeper or general coach despite having an AC ticket. The new rule may be effective in March.
A circular has been issued in this regard, as per Deputy Director of Traffic (Commercial) of Railways Rohit Kumar.