Hello,

The preparatory rank or prep rank is used to admit students when there is vacancy of seats. There is a specified seat matrix for every category in each institute. If the seats are not filled and remain vacant the counselling authority uses preparatory rank list for admission. The individuals will be admitted based on ascending order in preparatory rank list. This rank list is available for only those individuals who have reservation. Through this admission you are admitted to preparatory course of one year. And then you are admitted to first year of undergraduate course the next year.

When it says 57 on PwD prep rank list, it can be meant as wailting list number 57. You have 57th priority if there is vacancy in institute.