Recently a relative and family visited me and they had some change of travel plans. I booked tickets for them using irctc web site, only after booking did I know that they did not have any valid ID proof acceptable by Indian railways. Photocopies are not acceptable FYI.
As per the FAQ of irctc at https://www.irctc.co.in/beta_htmls/etktfaq.html#Q6
A. One of the passenger booked on an E-ticket in a PNR is required to present any of the ten identity cards noted below in original during the train journey and same will be accepted as a proof of identity failing which the passenger will be treated as travelling without ticket and shall be dealt as per extant Railway Rules. Valid Ids:- Passport / Voter photo identity card issued by Election Commission of India / Driving Licence issued by RTO / Pan Card issued by Income Tax Department / Photo Identity card having serial number issued by Central / State Government / Student Identity Card with photograph issued by recognized School/College for their students / Nationalized Bank Passbook with photographs / Credit Cards issued by Banks with laminated photograph /Unique Identification Card “Aadhaar” / Photo identity cards having serial number issued by public sector Undertakings of State/Central Government, District Administrations, Municipal bodies and Panchayat Administrations.
So if you have taken Aadhar card but you don’t have it at hand, you can go in for eaadhar, which can be obtained from https://eaadhaar.uidai.gov.in/
But mind it, you need know your aadhar number and your phone number registered with UIDAI (Unique Identification Authority of India). The mobile number is used to send the OTP for downloading the eaadhar pdf. Once you download it put it on dropbox or google drive or just plain mail it to yourself so that it can be downloaded and printed as long as you have net connection and printer. The password for the aadhar pdf file is the PIN code of you gave for your address.
If you don’t have your mobile to receive the OTP you’ll need the enrolment id which is even more difficult to have unless you have scanned it or have it with you.
Coming back to the problem faced by my relative, she did not have her aadhar number, but was able to call home and get it and had the same mobile registered with UIDAI (Unique Identification Authority of India). I got the eeaadhar and had a color inkjet printer. So printed it out and cut the ID portion of the page put it into a transparent plastic cover to look like original. Legally e-aadhar is considered legal and valid id proof as per the following links
But we know its India, if you just take a black and white printout and the TTE might say its not original, so better take a good color printout, laminate it if possible and then you can use it as original.
And yes, my relative was asked for id proof and TTE happily checked it and went ahead or she would have ended up with a huge fine and harrasment.