In general there are three main types of quotes that are available in the Indian Railways. These three types of quotes are General Quota, Remote location quota and Pooled Quota.
'''General Quota '''
The main quota for a train is popularly known as the General Quota. In other words, the General Quota can be explained as that quote which is normally for those rail passengers who boards at originating station or near the trains’ originating station and travelling to the terminating station or travelling for most of the route of a concerned train. The important thing to remember here is that general waitlist is started only when all the tickets under the General Quota are fully sold.
'''Remote location quota '''
Then in certain cases, few selected stations along a train’s route generally have their own reserved quota on a train. These stations are popularly known as the Remote Locations. As such their quotas are known as Remote location quota. When the quotas are big enough, these remote location quotas at times have a waitlist. In that case this waitlist would be the RLWL.
'''Pooled Quota '''
The remaining seats or the berths that are available would be for the Pooled Quota. This quota is actually for those people who do not belong to General Quota and also the Remote Location quota as well.
The important thing to always remember is that any of the above mentioned unused quotas are used to reduce the Reservation Against Cancellation (RAC) or Waitlist (WL).