Not only existing trains. Even New trains r been introduced in SER with old ICF coaches. See recently introduced Ranchi-New Giridih Exp, old ICF coaches used for inauguration and running.
Even for to be introduced Shalimar-Badampahar Exp, POHed ICF Coaches are comming to SRC for rake formation for inauguration and regular run. Why not LHB coaches allocated from RB for New trains?