1. Start-end: GNWL
2. Start-Short of terminating station: RSWL
3. Start-Intermediate Station (Falling halfway or before the entire train route): PQWL
4. Intermediate-Intermediate: Either or both falling halfway or close to the starting station: PQWL
5. Make check for 1 and 2. Usually they should differ. If not 2 would also come under GNWL. Depends from trains to trains.
6. Now make a check for 3 and 4. If A-B (According to criteria specified at 3), comes under PQWL, b sure B-C would also come under PQWL (According to criteria specified at 4)
7. Now again...
Read more...

for C-D (C happens to be the deboarding station for point 4/6 and D is the terminating station it should again come under PQWL)
8. Important point to note is:
If the journey leg comes under PQWL, then any combination starting from the previous terminating point should also come under PQWL. (PRovided the above criteria are more or less fulfilled)
9. Intermediate-Terminating: For all those stations for which PQWL does not apply, be sure the combination of the deboarding station - terminating /short of terminating station of the train would come under RLGN.
10. Now to distinguish between RLGN/RLWL and PQWL, be sure of the quota applied against a particular sector. If you know A-B comes under PQWL, then you can easily match the status against other sectors.
11. A train may have multiple RS and RL. In such cases PQWL may not be present in direct form and may have been distributed uniformly across the RS and RL. In such cases, even if PQ is present, RS and RL would support RAC (Due to its large share).
In other cases, WL status against PQWL would be more when compared to RS/RL)
12. If A-D availability is 200 and B-C is 400, (Train runs from A-B-C-D), you should realise that PQ quota of extra 200 berths plays the major role here). In such cases, you can blindly say B-C comes under PQWL. In such cases A-B/C-D should also come under PQ respectively. In cases where you find A-B/C-D availability less, it would have been allotted RS/RL. Here, to use the extra 200 berths from B, all the WL'ed passengers from A-B would be automatically cleared off. Same logic applies for WL'ed passengers from C onwards who would use the vacant berths from C.
13. RL usually follows RS. If you do not find RS across a train or may be PQ across a train, you can conclude that the quotas have been merged with one another.