What are soft and hard sleepers

A soft sleeper carriage has 9 compartments, in each of which there are four bunks, two upper and two lower bunks. A door separates the compartments from the aisle, providing a quiet and private room for the four passengers inside.
A hard sleeper carriage consists of 11 semi-open compartments. Each compartment has six berths going from two top, two middle and two bottom bunks. A ladder at the end of the beds is for passengers to go up and down. Basic beddings, such as a quilt, a pillow, and a sheet are provided.