Chennai: Waitlisted passengers who pay full fare may now find themselves travelling in higher classes, thanks to a revamped upgradation scheme issued by the Indian Railways. The new circular, released by the Railway Board on May 13, introduces a clear class hierarchy, and limits upgrades to a maximum of two levels. Launched in 2006, the upgradation scheme allowed automatic movement of passengers to a higher class without extra charges when seats were vacant. But it lacked a structured system. The revised version not only defines upgrade paths.For example, a sleeper class passenger may be upgraded to economy 3-tier (3E), then to 3A or 2A, depending on availability. But they cannot be directly moved to first AC. Similarly, second sitting (2S) passengers may move to Vistadome sitting (VS), then to chair car (CC), and from there to Executive Chair Car (EC), EV or EA but only step-by-step and not beyond two levels.The hierarchy is now clearly defined. For sleeping accommodation, the order is sleeper, followed by 3E, 3A, 2A, and finally 1A. For sitting accommodation, the progression is from 2S to VS, then to CC, EC, EV, and EA. However, upgradation from 2A to 1A is permitted, but only from 2A and not from lower classes. Similarly, EC, EV, and EA classes can be offered only to passengers coming from CC.Upgradation will happen separately within sitting and sleeping categories, and only full-fare paying passengers will be considered.Those who book under senior citizen or lower berth quotas are still eligible, but a warning will now appear during booking stating that they may not get a lower berth if upgraded. The Centre for Railway Information Systems (CRIS) has been instructed to modify the ticketing software to enable this alert. Railways has also made it clear that no berths will be blocked for current bookings during this process. All vacant berths are to be used for upgradation.If new travel classes are introduced in the future, the same rules will apply based on fare hierarchy and the two-level limit.Instructions have been issued to all zonal railways, and the revised policy has received financial clearance from the Railway Board.