India has some of the lowest train fares in the world, and even the fares for the more fancy and expensive higher class are still extremely low as per Western standards. (E.g. An overnight ticket for a bed in the air-conditioned compartment will cost around $20/person.)
The tickets for all trains can be bought online. For long-distance travel, reservation of a berth can be done up to 90 days prior to the date of intended travel. The tickets display the passenger's name, gender and age, as well as the travel class, carriage and seat number.
Train stations are equipped with electronic panels, which inform passengers where each single train carriage will stop even before the train enters the station! That is very useful as most trains are super-long and it would take forever to walk all the way from one end of the train to the other to find your assigned carriage. Additionally, next to the entrance of each compartment there is a list of all passengers that have seats reserved there! I have not expected to find this level of planing and organization anywhere in India, so that was a very positive surprise.
There are five classes of accommodation that can usually be found on Indian Railways trains, below listed in order from the cheapest to the most expensive:
- Second Class
- Sleeper Class
- Three Tier Air Conditioned Class (3A)
- Two Tier Air Conditioned Class (2A)
- First Class Air Conditioned (1A)
Below are short descriptions of each of the classes.
Second Class:
- no reservations required
- sitting and standing spaces only
- usually super-overcrowded
- super-cheap, price would be around $1-2 for several hundred kilometers
Sleeper Class:
- carriages are divided into open-plan compartments with six beds in each (stacked vertically in three tiers)
- there are also two tiers of beds located outside the compartments, along the aisle
- beds need to be reserved
- no air-conditioning, so it can get very hot in the summer
- noisy as usually windows need to be open to allow for a bit of cooling and fresh air
Three Tier Air Conditioned Class (3A):
- the carriages are laid out in the same manner as in sleeper class
- the passengers are provided with sheets, pillows, blankets, and towels
- the windows are covered with tinted glass and can not be opened
- air-conditioning keeps the carriages cool
- toilets are much cleaner than in the second or sleeper classes
- the conductor will wake up passengers half an hour before their destinations
- beds need to be reserved
Two Tier Air Conditioned Class (2A):
- same as 3A, but there’s much more space, as there are only four beds in each compartment (the beds are stacked vertically in two tiers on either side; there are also two tiers of beds along the aisle outside the compartments)
- there are curtains on the entrance to each compartment, as well as across each of the beds that run along the aisle, which add a bit of privacy
First Class Air Conditioned (1A):
- same as 2A, but compartments have lockable doors instead of curtains
- there is a carpet on the floor
- there are two or four beds, stacked vertically in tiers, no side berths
- the cost is around double that of 2A
- this class in only found on the most popular inter-state train routes
Whenever possible, try to reserve an upper level bed. They don't have to be folded down during the day like the middle level ones, or act as seats for all the passengers like the lower level ones.
The beds located along the aisle outside the main compartments (side berths) offer a bit more personal space (they are great for two people traveling together), but are a bit shorter than the ones inside the compartments (and, therefore, not recommended for people taller than 5 ft 10/178 cm).
On some trains there are women-only compartments, but you need to make clear that you want to travel in one of them at the time of booking.
In general, I would recommend booking tickets as soon as you know your travel dates. We were booking our tickets around two months in advance, and even then for one of the trains we did not manage to get tickets for 2A class and had to go with 3A. Apparently, both the train conductors and the station officers always have some seats at their disposal and can issue "last minute" tickets for them. However, I have never tried that, so I have no idea how it works in practice.