Why IRCTC doesn’t allow to check availability without login?

Why would webapp like irctc.co.in not allow to check train seat availability without login. As per my thinking it should atleast let people check seat availability without login and ask for credentials when he is proceeding for booking.

Now many of you may say: because of security reasons, then why flight booking webapps are other way?

Edit: I know question looks little off to community, consider this as a designer if you are re-designing it, you should have this info. Hoping that some other uxer might have given it a thought. Let me know if needs to be removed.