well this is a temporary thing...look after few hrs/a day and the booking will resume...the reason for rt cls suspended is somewhat strange and unpredictable...sometimes its due to technical reasons and a few instances hv been heard where rlys hv introduced spl trains and or want patronage of regular trains then rt cls is suspended for poular trains...once the booking of spl train is fulfilled, the rt cls suspended is relieved...strange but true...