WAM 4 - Father of the Nation for RailFans - Vikas Kumar

i just can under stand what does it mean 312 seats remain empty from gdr/ogl and from bza ?
You Queried For
Train Number Train Name Date
(DD-MM-YYYY) Source Station Destination Station Quota Code
16031 ANDAMAN EXPRESS 07-04-2013 CHENNAI...
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CENTRAL ONGOLE GENERAL


S.No. Date (DD-MM-YYYY) Class - SL Class -2S
1 7- 4-2013 AVAILABLE 312 Charting Done
2 10- 4-2013 AVAILABLE 8 NOT AVAILABLE
3 11- 4-2013 REGRET/PQWL100 NOT AVAILABLE
4 14- 4-2013 AVAILABLE 18 NOT AVAILABLE
5 17- 4-2013 AVAILABLE 18 NOT AVAILABLE
6 18- 4-2013 AVAILABLE 7 NOT AVAILABLE

LEGENDS:- GN-General, PQ-Pooled Quota, RL-Remote Location, DP-DutyPass, RS-Roadside, CK-Tatkal, YU-Yuva