The biggest problem with the coaches in Indian trains is that in cases of accidents like today's fire on the Samjhauta express, people can't escape in time. A second class sleeper coach can house 72 people. And there are 4 narrow doors and a narrower aisle and one or two windows marked as emergency exits. All windows have a metallic grill. So if the doors were to get blocked or jammed, there is no escape route.
Actually, shouldn't each window be an emergency exit, whose grill can be removed easily and quickly to allow people to escape?