Yes u r correct...by gross earnings data a zone cannot be judged....
A zone should be judged by Net earnings or by its Operating ratio.....Higher the Operating Ratio the bad is the zone performance in profit....Less Operating ratio is the best performing zone and Profit making zone......If we look at operating ratio then as i was telling earlier also if we look at net income of a zone then Best performers are ECOR, SECR, SER, SCR, ECR then comes others ....in that case NER, NR, ER, SR, KMR all in downwards direction loss making zones of IR