www.indianrail.gov.in/refund_Rules.html
ISSUE OF DUPLICATE TICKET IN LIEU OF TORN/MUTILATED TICKETS :
Duplicate ticket can be issued only in case of torn/mutilated confirmed/RAC tickets.
The duplicate ticket can be issued against torn/mutilated ticket if it is reported to the railway and the passenger can travel on the accommodation reserved by him, by making payment and getting a duplicate ticket as per following table :
A)...
more... Before the chart preparation
Under this rule the duplicate ticket (in lieu of lost/misplaced/torn/mutilated/reserved/RAC tickets) will be issued before the preparation of the reservation chart, duplicate ticket will be issued on the collection of the clerkage charge per passenger.If the loss of confirmed/RAC ticket is reported after the preparation of the reservation chart, duplicate ticket will be issued on the collection of the 50% of the fare
Refund on torn/mutilated ticket is admissible on torn/mutilated if its genuineness and authenticity are verified on the basis of of particulars visible on the face of such ticket .subject to the deduction of cancellation charges as per rules, provided that the authenticity of such a ticket is verified at the station on the basis of particulars visible on the face of ticket.
NOTE :
1) No duplicate ticket against lost RAC ticket is permitted after the chart preparation.
2) No duplicate ticket is issued against Wait List lost/torn/mutilated tickets.