What is the difference between Waiting List (WL) and RAC?
Waiting Ticket: If your ticket remains in the waiting list even after charting, you cannot even step into the reserved compartment (sleeper or AC). Online waiting ticket gets automatically canceled and money is returned.
RAC Ticket: Even after chart preparation, if it remains RAC, you can still legally enter the train and sit on your allotted seat. Railways cannot deboard you from the train.