Originally Posted by hserus

It had better be accurate - its there to prevent card fraud, especially with international cards if your details dont match up an audit might flag your card and cancel the ticket on you.

Indian trains may be crowded so pick the highest class you have availability in (or the lowest waitlist in). AC1 -> AC2 -> AC3 -> Sleeper.
AC1 is lockable coupes (with a door), with 2 or 4 seats per coupe.
AC2 is open plan with 2 x 2 seats + berths facing each other
AC3 is open plan with 3 x 3 seats + berths facing each other
Sleeper is like AC3 but not aircon