Indian Railways offers various types of coaches / classes that differ in the level of comfort, amenities, and fare. Here is a description of different train classes of the Indian Railways:
1A (AC First Class)
Most expensive class, with fares at par with airlines. Available only on popular routes between metropolitan cities. Coaches are air conditioned, carpeted, have sleeping accommodation and have privacy features like personal coupes. Bedding is included. Berths are arranged in two tiers.
2A (AC Two-Tier)
Second to the 1A class. Air conditioned coaches with sleeping berths, ample leg room, curtains and individual reading lamps. Bedding is included. Berths are arranged in two tiers.
3A (AC Three-Tier)
Similar to 2A, but with an additional berth (“middle berth”) in between the top and bottom berths. Hence more cramped, and cheaper, than 2A. Bedding is included. Berths are arranged in three tiers – the middle berth is kept folded during the day so passengers can sit straight; it can be erected at night for passengers to sleep.
3E (AC Three-Tier Economy)
Similar to 3A, but slightly more cramped. Introduced recently to make AC travel more affordable for people. Bedding is excluded from fare and is available on a payment of Rs.25 per passenger. Berths are arranged in three tiers.
SL (Sleeper Class / Second Class)
Most common coach. Regular, non-air conditioned sleeping coaches. Bedding not included. Berths are arranged in three tiers (like 3A).
FC (First Class)
Same as 1A, without the air conditioning. Non-AC, two-tier sleeper-type berths. Being phased out; available in very few trains now.
CC (AC Chair Car)
Air-conditioned seater coach. Present in relatively shorter-distance trains that ply between cities during daytime.
2S (Seater Class / Second Class Seater)
Same as AC Chair Car, but with bench style seats and without air-conditioning. Not very comfortable; suitable for short travels.
UR/GEN (Unreserved / General Class)
The only class type in which entry is allowed without a reserved ticket. Cheapest fare among all class types. Although entry into the compartment is guaranteed, a sitting seat is not guaranteed. Tickets issued are valid on any train on the same route if boarded within 24 hours of buying the ticket. These coaches are usually very crowded.
How to get train information in India (Seat availability, train schedules, fares)
Tatkal booking system of Indian Railways
How to book train tickets in India (Regular, Tatkal)
Popular train types in India (Rajdhani, Shatabdi, etc.)