what is the difference between tier 2 ac and tier 3 ac in a train?
AC 3 Tier (3 AC) The only discomfort is that instead of being 2×2 seating it is 3×2 seating. It has three tiers of bunks – upper, middle and lower on one side and two bunks on the other side of the aisle. It's more crowded than 2 AC, and lacks the privacy curtains and individual reading lights found in 2 AC.