Indian railways is a complex structure with buzzing crowds and also deserted compartments, all at the same time. You might have college students going for a trip, elders visiting their grandchildren, office goers trying to reach on time, school kids, travellers and a lot more. During this trip, the compartment in which we stayed was pretty crammed up, but the compartment next to us was quite empty, again after a few compartments, it was crowded and then again it was airy!