The move, which came into effect on October 26, is believed to be an innovative way for the railways to encourage passengers to link their Aadhar numbers to their online booking accounts on IRCTC.
IRCTC officials said passengers can continue to book up to six tickets a month without validating their Aadhaar cards.
If the number goes beyond six, the Aadhaar number of the user and one of the passengers should be updated in the IRCTC portal, an official explained.
Users on the IRCTC portal have to click on Aadhaar KYC under the 'my profile' category and update their Aadhaar number.
A one-time password (OTP) will be sent to the mobile number linked to Aadhaar and should be entered for verification.
In addition, the Aadhaar number of any one of the accompanying passengers should also be updated under the master list . This will be validated through an OTP.
The move is expected to eliminate malpractices in ticket bookings as touts and travel agents cannot create fake user IDs anymore.
In the IRCTC portal, six passengers can be reserved on a single ticket under general quota while Tatkal bookings allow four passengers per ticket.
The railways had announced in December last year that registration of Aadhaar with IRCTC was mandatory to avail concessions from April 1, 2017, but dropped the idea after opposition from various forums.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)