Don't you Think More or less the Railway Zones have become More of State Wise...
As in...
CR = Maharashtra
SCR = Andra Pradesh
SWR = Karnataka
WR...
more... = Gujarat
NWR = Rajasthan
ER = West Bengal
E.Co.R = Orrisa
WCR = Madhya Pradesh
SEC = Chattisgarh
SR = Tamil Nadu, Kerala
NER = Avadh/Purvanchal of U.P.
NCR = Middle/Lower Doab & Bundelkhand of U.P.
ECR = Bihar/Jharkhand