There are 4 class of sleeper trains in India in most trains... There is Normal Sleeper, then 3rd AC, 2nd AC, and at top 1st AC, There is also economy class with features of 3rd AC without cooling. AC class coaches are mostly safe. Sleeper is also safe but much more crowdy. I will recommend 2nd AC coaches, because you get curtains for more privacy, and 4 seats/beds in a compartment rather than 6 seats like sleeper and 3rd AC, but then where is the fun.... Sleeper and 3rd AC are more enjoyable.... many random things happen in those coaches.....She took 3A means 3rd AC