i know just 4 points about gnwl,rlgn,rswl,rlwl and pqwl. exceptions,may occur.
*what i know is starting to any station is generally gnwl or rswl or even pqwl. depends
*intermediate to any station is generally rlgn(also called rlwl)
*for several specific sectors in long distance trains pqwl comes into play.once allotted quota ends pqwl starts and it is same serial no.for origin to destination. also...
more... no rac in pqwl
*and for certain sectors where railways want top discourage travel but as train runs through it,so stoppage and quota is to be provided, it is rswl.
correct me if i am wrong