Seat Map or Coach Layout of Class AC 2 Tier in Indian Railways by etrain.info The 2A compartment is the Second Class AC, simply 2A , AC 2 -Tier sleeper etc. Regardless of what people call this compartment, on the train , it will always be mentioned as 2A . 2A is the second most luxurious coach in long distance trains in India, with air-conditioning and 2 tiers of berth on each side. Learn how to book 2A tickets on PayZapp, a convenient and rewarding platform that links your IRCTC account. But on the other hand, when you go online to book or reserve train tickets then you see all sorts of options like SL, 1A, 2A , 3A, 2S, CC, and EC. If you don’t know what these abbreviations mean, then you’re at the right place because we’ll be taking a look at what each of them means and why you’re charged differently for each section.