It's only for 3rd class air-conditioned. If you end up with the last seat or the first seat of the 3rd class air-conditioned coach, which is seat number 7, 8, 63, or 64, then let me tell you, your sleep at night won't be good. This is from my personal experience. I got seat number 63 in the B2 coach, and there are no curtains. Plus, the glass door of the compartment is see-through from the top, and it lets the light from the tube-light near the door come inside. This means there's no darkness while sleeping in these seats, while the rest of the passengers sleep peacefully in the darkness. I request the Indian Railways to at least put curtains on the compartment doors or attach curtains specifically on the last/first row seats, i.e., 7, 8, 63, and 64.