So you've got a few choices of train class travel when overlanding it in India. Although you've got 3 air conditioned choices (1AC, 2AC, 3AC), the next class is both cheaper, similar in accommodations and not that much less cool during the spring. Now, I could totally change my tune when we get to the super hot months, but for now (March), it's fairly pleasant, gets you face time with lots of Indians and saves you hundreds of rupees.
Tonight, on our overlander from Kotagiri to Chennai, we played several games of cards, had some snacks and drinks, visited with some local folks making the same trip, and tucked it in around 10:30. We've got 6 or so hours left to go, but with the cool wind blowing through with the overhead fans and gentle rocking motion of the train tracks to lull me to sleep, I could hardly ask for more. And for you US'rs, calculate this: 337 rupees (or roughly $7.50) gets you about 550 km's of overnight travel in what basically amounts to a nice hostel experience. What a deal!
Endorsement: sleeper class! Iiiiiiiiiiindiaaaa!